I use my T20C2 mkII with the neutral emitter and the SMO reflector almost all the time. The neutral modules uses an XP-E emitter so it basically like an XR-E (no donut hole) without the Cree rings. I has a tight hotspot for very good throw, enough spill to be usable (P20C2 will have more though, as will the XP-G modules), nice tint, and a smooth beam pattern. The low mode doesn't seem to be as low on the neutral modules as on the XP-G modules though, and the neutrals are only 190 lumens on max. Still those 190 lumens in the neutral will out-throw the 300 lumens from the XP-G - the extra lumens seem to be in a larger spot with more spill.
I also have the XP-G modules to experiment with, and if you're going to go that route you definitely want the OP reflector. The SMO module with the XP-G has a very pronounced donut hole effect, but the OP yields a very smooth beam. Throw is a little bit less with the OP, but the spill is a little brighter and it eliminates the donut hole - definitely a good trade-off if using the XP-G.