In the last week or so, I completed the Kestral and Rasalhague DLCs as part of my campaign. Kestrel was great. You can get by starting with two lances between 200-300 tons. Each segment of the campaign is at an industrial world so you get plenty of repair time between missions and the mech markets are flush with appropriate tonnage mechs in ready-to-fight condition with stock, maybe T1 weaponry. The settings are kind of fun. One mission involves a cough rogue mercenary element cough that attacks an HPG station. Another involves fighting through the first Cataphract mech plant on Tikonov. They're fun local changes.
Rasalhague was...far more challenging. The starting tonnage in the preamble missions should be a warning, but you basically start at 350ish tons and go up from there. The limit maxes at 400 at or before the third planet. This campaign is a lot more punishing. You basically need to start the main campaign (Rasalhague, Gunzburg, Radastat?) rolling in with at least two full lances of assaults and then a lance of 70+ heavies or better. Come with at least eight or more pilots, too. You can't buy/repair/hire at the first planet and even when you get to planets 2 or 3 the time between missions means a mech losing anything more than armor is out for the rest of the Rasalhague campaign. Some missions feature three-way fights which is works okay-ish in MW5 but needed a little more cook time, IMHO. Proof of the DLC logistics challenge: you'll earn an AS7-D and a STK-3F during planet 2 that have no legs. You cannot repair them in time to use in the same DLC you earn them as reward.
I came out of Kestrel rocking a significant tonnage upgrade of great mechs and gear but I came out of Rasalhague...lacking. I went into that campaign already owning: AWS-8Q, AWS-8R, BLR-1G, STK-4N, BNC-3S?, CP-10-Q, and an AS7-D. I did get a CP-10-Z in good shape and the STK-3F for repairs, but I think I sold the damaged AS7-D reward. I am not really a fan of the vanilla hardpoints in MW5. I know YAML's a thing but I'm trying to finish one game unmodded. I'd never played a videogame that size-locked the hardpoints, so it's really annoying that most mechs really can't do much besides stock. I can't really convert either Cyclops to the massive SRM-zilla monster I had in HBS BT.
I'm back out trying to work on the main campaign again which is super annoying after Rasalhague since I was trying to get to the "west" edge of the Marik/Steiner border and Rasalhague drags you up to the coreward north twice. Ah well.