I have had a 12v/gas unit in my earlier RV's and now a residential unit in my 33IK... My observations..
1) heavy, probably but so are 5th wheels
2) can use on 120v or 12v (via a "good converter")
3) have used one battery with no issues ( i do not typically dry camp)
4) always use while traveling, not sure why I would not? TV charging battery. Also no question about operating fridge with gas while traveling or going thru some tunnels with my fridge on.
5) more capacity than gas/120v unit
6) gets cold fast, do not have to worry about turning on way ahead of use and then making sure all the food I put in is already cold or frozen.
7) does not ice up or constantly drain water outside
8) I can stand in front of the open door and wonder what I want without worrying about letting all the cold out :
9) I can have my vanilla ice cream that is actually frozen
I think the biggest trade off is how you camp. If you do a lot of dry camping then a residential is probably not your best choice but if not, you will love the residential unit imho...