I'd strongly recommend getting the later Rega table with the straight tonearm. The later Planar 2 had an RB250 on it, and the later Planar 3 had the RB300 on it.
The older curved arm was not in the same league as these other 2 arms.
That being said, if you plan to use a relatively low cost mid-compliance MM cartridge on it, the curved arm should do reasonably well in that role, but never up to the same standard as the straight Rega tonearms.