We had an opportunity to test the Combat Elaborations:
Initiative that Matters
Clarified Round Structure
Revised Armour Saving Throw procedure
First Round was just a few single combats and an overwatch unit.
Next Round saw 16 bad guys show up and then the hurting began.
By the end of the session, we had two PCs down but passed their Survival Rolls (but not easily), and a random event which really helped the PCs and had a great in-game rationale. The bad guys were not well prepared to fight in the dark and when the lights went out, it was like shooting fish in a barrel.
Situational Awareness can make life and death difference: one missed Clue roll and then Personal Saving Throws were unavailable, as also happens when Prone (such as when each leg receives a wound).
Critical Strikes are increasingly common as the PCs level, and their opponents are generating them as well. Ouch.
For lots of [optional] bells and whistles, it runs gruesomely well: more like MERC than Phoenix Command. Using Mass Combat rules instead drops figures much more quickly in table time, and is D&D-level abstract, which is great. Three scales of combat with a lot of interchangeability of optional rules so that the mass combat can easily include a basic or advanced Hit Location roll to determine whether hard cover blocks a body part, or, at the bells and whistles scale, simply remove figures once their Armour is penetrated. Options and speed.
Good testing session, and the Shadow Warlock didn't blow up the universe. :D