For years, I couldn't stand playing someone else's signature guitar if it was either so iconic that everyone knew THAT guitar was designed/made for someone else, and I still think owning signature guitars is tacky. This is another reason why I love Les Paul Customs.
Unlike the Gibson/Epiphone Les Paul Studios/Classics/Standards/R8s/R9s/R0s, the Customs are the only Les Paul that does NOT have a Signature or have Les Paul's name on it! The only area that mentions "Les Paul" is the truss for cover, and I always replace the truss rod cover with a custom made cover!
Over the years, there have been quite a few guitars and amps that I've really liked and came perfect for me from the factory, but for some reason, i hesitate to buy a Signature guitar or amp. It's all personal preference, but I can't stand to own or play someone else's signature, even if the guitar is hard to find in non-signature or pre-signature models. Take for example the G&L Rampage. I love Jerry Cantrell's tones, and I would love to buy a Rampage with a Kahler, but they're harder to find than his sig model, but I just can't bring myself to pull the trigger. Another example is the Zakk Wylde Les Paul Customs. Zakk has some great tones, but I couldn't ring myself to buy a bullseye LP because it's so iconic, it would make me seem like some Zakk fanboy, even if I played it using Mixolydian scales over 400bpm paradiddles in drop A.
There are a few exceptions of signature guitars that are great guitars that will help you cop the tones of a few guitarists, without being a walking fanboy billboard. For example, ESPs Hetfield Explorers and Eclipses. They're all designed by James, but with the exception of the Iron Cross or the Snakebyte, they don't feature iconic paint jobs or signatures under the clear coat.