Qcad is commercial software. The author is doing his best to ride the line between commercial and OSS, but most free software developers don't want to play. LibreCad was forked from an earlier version of Qcad and fell behind. Now they're doing a whole new LibreCAD but it's been years in the making.
As a user of QCAD I am more than happy to pay the extra for the features in the commercial version and support the developer (Not vastly different but adds a few tools that make certain constructions easier). I used it free for a while and appreciated it enough to exchange some money. The extra features are a bonus but it's worth the money even for the free version.
I think it's a shame that LibreCAD has stagnated and diverted, particularly on usability. QCAD has one of the best 2D CAD UX I've used, akin to AutoCAD but more light and nimble. Exactly what is needed for most 2D CAD.
If you need a powerhouse, then you really need 3D anyway, and most likely you aren't a hobbiest if that's the case. For 2D, it's QCAD all the way. 3D is nice, but 2D gets the job done 9/10 times. 3D is overrated.
LibreCAD v3 is very nearly abandoned. I could be wrong, but the vast majority of the new code there came from GSoC students who didn't quite stick around for long except just one who did multiple GSoCs but also eventually left.
