From our table, the Reaper is a great expansion for the money. Adds some more claustrophobia and 'take that' to the base game. I'm not a fan of the expansions that add more board pieces as it decreases player interaction. So, The base game + Reaper = outstanding. Plus they both fit in the same box. A big plus for me as space is an issue.
So, I've been thinking about picking up the Frostmarch. Took a look at some pictures of it over on BGG and apparently the minis are different sizes. Now, I'm already having to settle my "minis-ocd" with that over-sized dwarf mini in the base game. Not excited about the prospect of paying for a bunch of minis all out of proportion with my current ones.
Sure, the minis don't take away from the gameplay, yadda, yadda, yadda. Minis add a level of visual appeal that pawns and stuff lack. However, if the minis are all whacked the visual suffers. If FFG isn't going to stick to a consistent scale, I'm seriously considering using pawns or some other marker for the characters. This'll save on painting time too.
Anyway, I guess this is a non-issue for most here. Just ranting a bit, as I really enjoy the new FFG Talisman. This sucks.
The Dungeon expansion also fits into the base game + Reaper box, without removing the insert. Your cards might not fit in the same way though, you'll need to stack them on their sides.