First of all, if you played NYGM, you will have a shock when you will experience the loading times of WAC and LSH
Otherwise, they are both great mods, lots of nice visuals and top mods in both . Also, you can copy a "pristine" SH3 install in a separate folder(s) and install them both .
Of course SH5 looks better, especially now with supermods like Wolves of Steel, however, for me ( and i noticed other members saying the same thing), no other SH game matches the atmosphere and immersion of SH3 .