The difference will more likely be that the slide-in will have controls on the front and no raised control panel on the back. The slide-in will also need (maybe) a strip of counter-top material between it and the backsplash/wall.

In my opinion, it really just is a matter of aesthetics. I prefer the look of a slide in, and that's what we chose for our kitchen. My neighbor has a free standing and it looks fine as well, but I still prefer ours.

Agreed, personal preference. I prefer slide-ins, I think the lines are cleaner looking. You will also see more of your backsplash with them. But be aware you'll be dealing with controls in the front, which for some is an issue, for others not so much. They've improved them now so the controls aren't quite so touchy, but I'd ask for a demo and find others who have the model you want : )

I was all set on a slide in, but I had to get electric (no gas in my neighborhood). The reviews for the front controls on electric slide ins weren't great. So I ended up with a free standing range. I agree that slide ins look better, but read up on reviews on both and then decide what you are willing to deal with.

Also consider if you are going to studs you may decide you want a separate wall oven and built in cook top with pots and pans drawers underneath. So maybe getting something cheap and temporary is a better option. You could probably sell it later.