Aug. 7—A decent electric bicycle will typically run you a bunch of money.

Bicycling Magazine estimates a good e-bike will cost at least $1500 — though you can get away with $1,000 or less in some cases — and a top-shelf model with a propulsion system from a top manufacturer will increase that minimum to $2500.

But would you pay $4,000, $5,000 or more for an e-bike? Companies such as Karbon Kinetics and Specialized have been testing this proposition with fancy e-bikes positioned as state of the art.

Last year I told you about Karbon Kinetic's Gocycle Gˣⁱ, a futuristic e-bike looking little like a regular bike, with a clever folding system for storage and loading onto autos and public transport. The Gˣⁱ retailed for $4,799. It has since been retired, with a different model, the G⁴ⁱ, going for $4,999.

More recently, I've been trying out a couple of Specialized's Turbo-branded bikes that look little alike but share core tech.

One of the Turbos I tested, the Como SL, is a casual bike for commuting, getting groceries or hitting a cafe. It has a plastic basket in the front for cargo, and a rack on the back for more storage using pannier bags. The Como SL costs between $4,000 and $4,800.

The other one, the Vado SL, is for more adventurous, aggressive riding on paved roads or gravel trails. But it's also a practical bike for commuting, with a bag rack, along with lights and optional fenders. The Vado SL costs between $3,600 and $4,750.

Dead-easy operation. Some e-bikes have a bit of a learning curve (I'm looking at you, Gocycle), But Specialized's system is a breeze to master.

On the Turbos, the top tube incorporates a power button along with illuminated readouts. One of these shows battery level via 10 stacked blue bars.

Another is a circle that fills in partly or totally, depending on how much the battery is engaged. This is indicated via three modes—Eco, Sport, and Turbo. Eco provides the most range but the least amount of pedaling help, while Turbo offers the most power at the greatest expense of battery life. Press the circle to shift among the modes.

You can also engage the modes on the left handlebar using a small shifter that a casual observer might mistake for a gear changer or bell button.

Neither bike has a throttle, which on other e-bikes functions as a sort of moped mode to travel without any pedaling. You always have to pedal on the Como and the Vado — though with varying degrees of electrical assistance, along with mechanical gears via a handlebar shifter. (I'm just fine without a throttle, thanks.)

Where's the battery? On most e-bikes, the battery is hard to miss as a bulky object that is grafted onto the frame. This invariably looks hideous.

On the Turbos, the battery is nowhere to be seen since it's incorporated within the frame. Looking at the bikes, in fact, you can hardly tell they are electric.

But if you want to go farther, Specialized offers battery attachments called "range extenders" that go into a holder similar to one for a water bottle, and plug into the motor to augment the integrated battery's capacity.

The extenders mar the bikes' aesthetics but give them far greater reach. On the Vado SL, a maximum advertised range of 80 miles jumps to 120 miles with a range extender.

There's an app for that. Like Karbon Kinetics' Gocycle line, Specialized's Turbo e-bikes have apps. This basically turns them into super-fancy phone accessories, and allows users to adjust the bikes' settings on their iPhone or Android screens.

Specialized's e-bike app, called Mission Control, lets you access the same Eco, Sport, and Turbo modes found via the physical controls—but, in the app, each of the modes is adjustable. You can tweak how much battery support and peak power each provides. You can create new modes, as well, and give them names.

The app lets you plan an outing and stay on top of the data it is generating. Its stats screen displays your current speed, distance, battery level, time from start, and more. A map shows your location. The app also archives your outings, including maps.

By far the most interesting and useful part of Mission Control is Smart Control. It lets you automate battery consumption based on a range of factors, so you are assured of having sufficient juice to complete a ride, and then some.

For instance, you can tell Mission Control roughly how long a ride will last, how much distance you will cover, or what you want your maximum heart rate to be (using an external sensor you provide). Within each of these categories, you can adjust subfactors, like elevation, climb response, and how much battery charge you want remaining at the end. The e-bike then metes out the required amount of power for the entirety of the outing, regardless of what conditions you encounter.

Which Turbo model to get? I enjoyed the Vado SL enormously. As a road-biking enthusiast who has logged more than 10,000 miles on my beloved Bianchi in the last few years, it was good fit. I was nursing an injured knee when the Vado SL arrived, so it was a godsend in allowing me to continue riding as usual while putting less stress on my aching joint.

The Vado SL is a lot less expensive than Specialized's Turbo Creo SL, which is an electric road bike that starts at $13,500.

I didn't like the Como SL as much. It's not my style (though I found it to be an intuitive and satisfying ride after all my time on the Vado SL). With that in mind, I tried it on a friend who is a far more casual cyclist on the theory that she might get more of a thrill out of it. But she hated it, finding it ungainly compared to other e-bikes she has used.

My testing of the Como SL was marred by horribly unresponsive gears. This was possibly due to the fact that my review loaner was not new and sent to me directly from Specialized, but had arrived my way via another tech reviewer who had used it hard before relinquishing it. Still, if you are considering this model, be sure to thoroughly test-ride it to be sure it is to your satisfaction before handing over your credit card.

For what it's worth, that writer at The Verge calls the Como SL "an absolute delight to ride."

But is it worth the scratch? Ah, that's the key question, isn't it? Fancy e-bikes like the Como SL and Vado SL cost more because they come from top vendors, have higher-end parts, and throw in gee-whiz features such as app-based adjustability. To a large extent, you're paying for the brand — Think Apple devices, which often cost more than equivalents from other makers. But, like Apple, Specialized offers incredible quality; the Vado SL is by far the best e-bike I've ever tried.

That's great for those who can afford such models, but mere mortals have to look much lower on the e-bike food chain. Options include the Lectric XP that I told you about last year, costing around $900.

And inner-city dwellers like me have to weigh the possibility of our bikes being stolen. I therefore never take my Bianchi on errands, opting instead for a cheaper, beat-up touring bike that is less likely to draw attention while locked to a bike rack outside a supermarket or public library.

So while the Como SL is marketed largely as an errand-running bike, I never dared using it like that since I would have had to leave it unattended out in public for lengthy periods. That's something else to keep in mind when considering one of Specialized's souped-up Turbo e-bikes.