For a lot of cases, the libre engine it's far better than the original one. For instance, Exult for Ultima VII or ScummVM, which today runs far more stuff than Lucas Arts and Sierra games.
I spent some time looking into it a few months ago, and TR1x was easily the least sketchy and most reliable of all the engine re-implementations I could find, probably because it's based on a decompilation rather than completely from scratch.
Well, I meant about the build process on OpenLara; too complex to follow and it used c++ which was hard to fix some compiling errors.
The easier one uses GL 3.3 and that was a no-no in my netbook, which supports up to GL 2.1.
For more libre game engine reimplementations: https://osgameclones.com
For a lot of cases, the libre engine it's far better than the original one. For instance, Exult for Ultima VII or ScummVM, which today runs far more stuff than Lucas Arts and Sierra games.