Welcome to the site! I am fairly new here also so there are much more qualified people to answer your questions, but here are a few suggestions to help;
1. Cost. What do you want to spend. Ballpark figure, you will need to spend twice the money to get a hard floor compared to a soft floor for a similar spec'd unit.
2. Type of camping. Do you move daily (go a hardfloor) or prefer to base yourself somewhere (go a softfloor). I have just bought a softfloor camper as we will generally not move around too often as we have two young kids. The other advantage to the softfloors is that you will generally get more canvas space and more storage space in the trailer. Suspect that as the kids get older and I get lazier the hardfloors will become more appealing.
All the best with your research!