I live in Riverview. My husband and I have two little kids so my review is from the stand point of "families with young kids". The town is a suburb of Tampa. It consists of brand new communities mixed with trailer park and the occasional cow fields. Besides grocery stores, a couple of big chain stores and a few chain restaurants there's nothing else. There are lots of military families b/c of MacDill Air Force base so I feel no community involvement because people move in and out frequently.
You can get a doze of mild entertainment just north in Brandon: mall, handful of restaurants, a movie theater that serves as a child care for teens Fri-Sun. Tampa is 20-30 min ride away with more stuff to do.
My biggest dislikes are education - public schools are terrible and focus on standardized tests, a few charter schools are too new - and lack of green space. Yes, you would think its Florida, how can that be? Well, there are few public playgrounds/parks and all at least a 15-20 min away, most communities have playgrounds too. But the biggest issue is they are not covered. And with temps of 80F+ 10 months of the year you can forget about playing outside after 10am. The playgrounds get so hot, kids get burns. The beaches are not close. A great beach on Anna Maria Island is 45 min away. I know it's better than no beach at all, but still it will be an all day affair. So most of the time your kids will be inside. Of course for older kids there are sports activities.
Overall I do not recommend this area for families with little kids...or with big ones either because of bad schools. Unless you're single and live in Tampa or a retiree looking for warm place to settle, you will not like it here.