I vote for trainer as well. It takes less space, for one, and while I'm not really familiar with prices, I would imagine the trainer would be cheaper. My husband has bought a couple of trainers, so he's more in the know on prices and brands and all that. I do know that the one we used to have I could put the bike on fairly easily. It was as another poster said, I took the skewer off the rear wheel to do it.
One reason I prefer the trainer is that I like to ride my own bike. I'm used to the feel of it and like the familiarity when on a trainer as well.
My husband just upgraded our trainer to a much nicer one, but while it's very nice to ride on (feels a heck of a lot more like being on a road than our old trainer), you do have to take the back wheel off to use it. I, therefore, have yet to use it except once when my husband set it up for me.
I generally avoid trainers at all costs, truth be known. I have to be pretty desperate to use one, as I by far prefer to ride outside on real roads. Riding on a trainer (just like a stationary bike) can actually be physically harder, because there is never any coasting like a real road. You're just constantly "going" . . . but not really getting anywhere! And no wind to dry your sweat.
Okay, I didn't mean to be a downer! GET A TRAINER! WOO HOO!!!!

(One upside is you can watch TV while you ride.

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