Practice wise, they really seem on par with cartridge, IMHO. I don't feel like I have any fancier technique or am especially careful when using it. I really use it like a would a cartridge. Changing blades means loosening a nut instead of popping off the blade--but I much prefer having 100+ cheap spares so I don't give a second thought to swapping for a sharp blade compared to only having a dozen cartridges onhand (because I lament spending $25) and having to remember to buy more. The only clear downside is flying (in which case, use cartridges when on the road until TSA lightens up).

The main thing is that you don't apply pressure you just let the razors weight and sharpness of the blade do the work. Only nicks I have ever gotten is when I messed up my hand placement due to lack of attention when flipping the razor and the corner of the blade got me.

I don't know how long the multiple blade razors take but if I have a weeks growth of hair it takes me 3 times going over to have a smooth shave (once with the grain, once across the grain, and once against the grain) though I usually forgo the against the grain and the shave is pretty good.

Overall time it takes is 10-15 minutes including filling the sink with warm-hot water, lather, shaving, and cleanup.

It takes a little more time, but I think that's because I now take the time to do a better job. For the same effort as a disposable, I think I'd still get a better shave.