I'm not opposed to buying a monolithic light if its design particularly appeals to me, but when it comes to a light that meets a specific functional purpose, I much prefer modular lights so I can upgrade them easily in the future.
If he's already got a Surefire tube to drop it into, that's a perfectly usable option. But if he doesn't, then buying a dedicated light like that works pretty well too - and with fewer parts to fall out or lose. That, and he'd be spending at least $120 on the Surefire and then more on the drop-in... only to set the expensive part of the light aside.
The TK35's a good option for semi-compact; it's more compact than some of the lights I can name which put out a similar or greater amount of light (Olight SR 50/51/91/92,Thrunite Catapult V3), uses easier to find batteries than the Maelstrom S12 or S18, and is lighter than the Fenix TK41 or TK50/60 series. That, and the low and medium modes are very usable outside; you don't usually need to go past High if you need a lot of light.
And if I was to recommend a Surefire with 800 lumens with an LED if there was no budget to consider, the UB3T's out there...