Don't worry about the manufacturing quality--that's a non-issue. If you can stand all the mailings, a mail-order club is a great way to get your feet wet. (I started my classical record collection with Musical Heritage Society 20-odd years ago.)
As for the quality of Naxos, there are bad performances on every label, and until you've really gotten into classical music, you're liable to pick up some dogs no matter how much you spend. So what? That's part of the learning curve. The great thing about Naxos is, it doesn't cost you much to experiment. And experimenting is exactly what you should be doing right now. Buy 'em by the fistful!
As for the quality of Naxos, there are bad performances on every label, and until you've really gotten into classical music, you're liable to pick up some dogs no matter how much you spend. So what? That's part of the learning curve. The great thing about Naxos is, it doesn't cost you much to experiment. And experimenting is exactly what you should be doing right now. Buy 'em by the fistful!