Remember, the first 6 feet of a MH is taken up with driving. So if your comfortable with a 30 foot MH a 30 foot trailer will feel really huge.
In that lengths though I would suggest a fifth wheel instead.
Motor homes are the number one most expensive RV outaide of truck campers. On a 30 foot Motor Home, think 3000 dollara for a set of tires just as an example.
Basically all RVs will have the same appliances, fixtures etc. So that is a non starter. With a motor home you will have two drive trains to maintain. With a towable a single drive train.
Bottom line, floor plan and livability for you are your number one criteria. Pick a floor plan you think will work and go play house for a half hour or so. Pretend your making a meal, taking a shower, sleeping etc. Make notes of likes and dislikes. What works for a weekend could be a deal breaker for long term. Heck we walked away from a great trailer simply because there was no place for a garbage can.