They all are good. I would go to the store and play with each to se which you like.
If the phone cannot be replaced ( like for like ) then try the OS upgrade.
You can follow JL_cmdr for a complete replacement of the OS or just try an upgrade by downloading the latest version. If you already have the latest then do a replacement. Either way if it works your all set. if you really want a new one then go for it.
Good luck and welcome to the forums
If someone helps, tell them by clicking the Thanks button.!! î
Z10 on BES