I like the Magpul handguards. Cost effective, and good at what they are, which I consider to be a simple, more ergonomic replacement for the stock hand guard.
They are NOT stable enough to mount any sort of optics on; maybe a light. They are nothing like a bolted on free float tube. I don't ever mount anything to them; bipod, front sling attachment, ... all go on the small gas block rail. But I do think they made a comfortable grip.
I did have the issue with the heat shield on the first one (fixed by over smashing the rivets, if I remember correctly), the 2nd on right below is a later revision and the heat shield is screwed on.
These are my twins, S&W M&P 15 OR on left, and CMMG .22 on the right.