In your position I would make a list of all trailers currently in production. Two-thirds of the RV manufactures shut their doors when the bankers destroyed the US economy in 2008. Then create your own chart of dry weight and holding tank capacity and sleeping options and fridge size, etc. and tabulate the information for each model. Along the way you will get a sense of the "normal" configurations and where one trailer may fall short and another provide extras.
There are trailer specific forums like the one for Lance trailers and also the forums on www.irv2.com and in these places you can find postings for problems that owners of various trailers have encountered. One make in particular has had structural problems from the manner in which the axle spring supports were attached to the trailer and this is an expensive repair.
The trailer manufacturers use the same companies for the various parts that go into their trailers in terms of the fridge, furnace, water heater, stove, so it is not likely to be a problem which trailer you buy in terms of these components. It is more the structural integrity of the trailer and how well suited it is for 3 or 4 season use if you plan to use a good portion of the year.