Drums do dictate technique to a large extent, and you will encounter some differences in playing. Among my regular gigs, most are using acoustic kits, but one monthly gig has me on a Roland TD20. It takes about one set to get acclimated to them, as the response is obviously different, but I'm fine after that. Returning to acoustics requires no adjustment time - it's immediate.
But since you're playing differently on pads, hearing really nice samples with cool effects, it's not necessarily a substitute for acoustic drums. In an extreme example, if you'd learned to play drums exclusively on pads for 5 years, never touching an acoustic kit, you'd probably have a really difficult time getting with the acoustics not being as forgiving and smooth as the V-drums. Yet, playing acoustics and then going to V-drums, the transition is much simpler.
Also, you'll get spoiled by the sounds in the V-drums, so it's a little strange going to an acoustic kit. And heck, they're a lot of fun!
So to answer your question is, they're different animals, and some of the techniques on one won't crossover to the other. Cymbals react differently, and dynamics are different between the two. So if you absolutely can't practice any other way, it's better to practice on V-drums than not practice at all. But if you want V-drums just so you can practice at 2am, I'd say save your money and get some sleep instead.