I agree ... Phex is a good client (and I've tried numerous ones myself). And yeah, it needs some work on the code. Being a cross-platform program written in Java, it would really skyrocket in popularity if it had more features and optimized code. I personally need something automated, retrying searches and downloading search matches on its own without my intervention. Phex comes closest to this compared to other apps. The "candidates" feature is really good, but still leaves more to be desired.

I'm learning Java in the meantime just so I can customize my own copy of Phex, perhaps releasing a whole new app.