Underpowered is a pretty broad term. I've never had a single gripe about the performance of my SAM 440, but then again, I never bought the thing with any intentions of trying to encode video or do rendering or something on it.
It does everything I ask of it, which admittedly are "Amiga only" type things. I don't expect it to stream video in 4k like the dual 980 GTX, 6 core, 64 GB RAM PC I'm typing this on, so I've never had much to complain about with it.
It's a niche/hobby system, one that was fairly pricey, I'll admit, but it's been a good experience for me, just like my MOS machines have been.
