If you can do a conversion yourself, you are way over qualified to fix anything that happens to go wrong with an RV.
Most of the stuff that goes wrong is trivial to fix or prevent. Many of the complaints you see have to do with water leaking through seams that aren't sealed, components that weren't even made by the manufacturer failing or things shaking loose over time. Stuff happens.
You move a slide out every 4 days for a year or two and you might have a motor bind up on you. Drive 15k miles and you may have a switch get disconnected or a ground come loose. Plumbing rattles loose. Most of the stuff is pretty easy to fix.
If you're reasonably handy and stay up on the big things like keeping your windows, slides and roof area sealed the actual guts of the RV and components are pretty easy to fix on a case by case basis when they ultimately fail.
For the most part people that are happy don't post. What is there to gain by going into damaged threads and saying "yeah my stuff all works sorry lol".
Let me also tell you that you do not have to go high end to get something nice and decent. We've had some relatively high end units in our time and they aren't double better than the middle market stuff.