Maybe not too high though maybe 4 or 5 levels because I'm a very particular when it comes leveling up and mine are pretty much always higher then the game because I like grinding battles in the grass so that helps and I battle everyone I see so they add up with the addition of the EXP share and the gaining EXP for catching and not just defeating them it kind up speeds up the process(takes away the grinding too :>)..and they end up being too high so I kind change what I do in the newer games..

I guess if I had too chose then I would pick over because sometimes the opponent is too strong or it's too hard to train Pokémon.