Learning other peoples solos is fine but I have a problem with it as a method of learning to play guitar...
Say you try learning something by Kirk Hammett, you are trying to emulate someone elses style. That's the problem. It has taken Kirk his whole life to get that style, use of vibrato and frequently used patterns. It doesnt mean that you won't be able to play the way he does, but you won't be doing anything new. I believe that you only start learning how to really play when you work on your own material. I have never played in a covers band so my approach to tab has been for getting a handle on exotic and difficult phrasings.
Playing covers is a fun way to get started but don't spend too much time on tabs alone. They are only a part of the learning process and will contribute little (but not nothing) to the creation of your own style.
One cool way of learning constructively from tab is by attempting some classical pieces. You can apply your own style without being influenced by someone elses inflections while playing over the backing music. There are some really cool pieces out there that sound amazing with a metal approach. Check out all of the great players that were influenced by the great composers who created their own style eg. Yngwie Malmsteen, Michael Romeo, Randy Rhoads, Steve Vai, Marty Friedman, Jason Becker etc etc etc