I've owned 2 Thors (not C's but small Class A's) and were very happy with them both and had minimal issues with either. I found Thor to be a delight to deal with as far as customer service.
The trick is having realistic expectations. Just about all entry level brands are built within the same quality range. They all use the same materials, same refer, same heaters, same AC, same generator, same chassis etc etc. I have heard horror stories from every brand. They are all made cheaply made when it comes down to it. There are however differences in slide mechanisms so do some homework. But don't expect quality and fit and finish from a $50k RV to be the same as a $200k one. Just like like any other product. But lucky or not, my 2 Thors served us well with no real issues. I am handy and do a lot of preventative stuff and mitigate problems before they happen. I also don't consider broken drawer slides, or failed cabinet hinges as "big problems". Spend $10 at Lowes, fix it yourself and move on.
Another plus is having a dealer you can trust and does good work - and that goes for any brand of RV.