I have a few MTB that I bought sometime ago. The epic is a L frame and the stumpy is M frame. The stumpy has cheap components and the epic has a nice fox fork and the rest of the components are nice. The stumpy has the rl rear shock, but I have another syumpy L that has the RLc rear shock and I really like it.
I'm around 5'9" and I believe my size frame should be M. I've been riding the epic for the past month and I really like the bike, but in only ridden the bike for less than 2 hours each time so I don't know how it'll work in longer rides or for a few years and if I'll be hurting my back on the long run. I used the fsr stumpy today in the trails and I didn't like it that much but I don't know it it has to do with the components, remember the syimpy has cheap components, the fork is worth nothing.
So my question is now, for trails I'm not a racer would it be better the stumpy if I swap all the nice components from the epic?
Does the epic feel so good because of the better fork and components or the epic always feels better over the stumpy.

Should I keep the epic for trail of just build the sj fsr?

Thanks in advance.