Posted 05 February 2016 - 11:31 AM
You have the two best variants already, so which you round out the trio with comes down to what you want to do with it.
If you love dakka, and I mean really love dakka, then go 5P... otherwise, don't. The 5P is a one-trick pony; 2xUAC5 is really the only build it can do that's really good... and the only reason it's better for that build than the 4P (which has enough space in its ballistic arm to fit 2xUAC5, plus better hardpoints for supporting weapons) is because of the quirks PGI gave it. Literally everything else you can mount on the 5P can be done better by one or all of the other Enforcers.
The 5D is like a not-quite-as-good 4R. You can still do quite a bit with it- 3xLL or 3xLPL, which are both powerful builds right now, or AC10/LB-10X + lasers, or 2xAC5 + lasers, and so on. Lots more build variety than the 5P has. It has a higher engine cap than the 4R, which you can really only take advantage of with a laser build. Not a bad 'Mech by any means- all of the Enforcers are good- but just not as strong as the 4P and 4R.