Worth it is a hard thing to quantify. Mechanically, it's a subpar choice to go more than 5 levels in gunslinger due to the opportunity cost of doing so. The best thing about going gunslinger is dex to damage with firearms/crossbows, and since you can always use more feats, jumping into fighter/monk/ranger/etc generally yields a better character, making straight gunslinger a lacking choice.
Gunslinger 20 is viable, it's not a bad build, but it's not optimal, which is why some people (like myself) advice against going GS 20.
|Darksol the Painbringer|
|The Wyrm Ouroboros|
Darksol, I believe the issue is something about getting outscaled on the damage issue, followed by the fact that there always seems to be a chance for you to explode. :P I did have fun with a ninja sniper + musket master, but I suppose that's an argument against going with gunslinger all the way ...
As of the last errata to Ultimate Combat:
- Pistolero and Musket Master can no longer ignore misfires. Don't be unlucky!
- Pistolero can no longer use Signature Deed on Up Close and Deadly. But that's not so big a deal now that...
- Signature Deed has been nerfed so that it can only be used once per round.