Welcome to Flyertalk, Enda.

Tab (along with Iberia Plus) are indeed OW FFPs that you are better off avoiding.
To some extent, it depends on the general pattern of your flying beyond the RTW. BA is a possibility but you may also want to consider AA.
If you consider the latter, you may want to read up on the Gold/Plat challenge for accelerated elite qualification on the AAdvantage board (see, in particular, this thread.