I think they are decent Inverters, but inverters are probably the most problematic of any electrics in a Motorhome so having a good route to service is important.
Victrons support is really down to the dealer you get the kit from - they are the ones who sort out the problems and get the swaps sorted. With
Victron kit I have bought I have generally got new parts sorted out without having to send the faulty parts back for testing or even swapout and been hassle-free. How much value should you put on that?