Go look at both. I recently went to an RV dealer who had Lance, AF and Bigfoot on the lot. The space with the slideouts is so much more comfortable. As much as I like the outdoors, I do end up spending a lot of time inside my RVs be it because of weather, cooking or just reading on my laptop. I will be buying a heavy camper with a slide as a result. Further, there is no place for my dog on the floor of a Northern Lite or Bigfoot. She would be miserable.
I'd add that if you're just going to be a weekend warrior during the summer, never using the camper in the winter or inclement weather, then perhaps a non-slide would be just fine because your outdoor space is as big and comfy as you want it. But if you're going to be full-timing or something approaching that, I think the bigger the better.