There is one good thing for bassist with some of these signature basses. If you play in a tribute band, then you can get the right looking bass for the job.
For me, some of the Sig basses are nice and some seem pointless. The Tony Franklin one is good but for the reason being it is the only fretless Precision Fender make. Why they don't make a fretless Precision in standard or have it as an option is beyond me especially as they have re-issued just about every model they have ever made over the last 10 years or so. The Flea bass I actually like. I think it's a lovely bass and sounded amazing. If I bought one then I would change the Flea neck plate and probably strip all the paint off. However, a Flea sig bass to me should really be a Stingray so the Fender offering is just a nice vintage looking Jazz bass to my eyes.
The Adam Clayton basses make no sense to me. Adam is more famous for playing a beaten up Sunburst Precision, not some sparkly Jazz thing.