Yes of course they are worth buying, some of the best RPGs in history. The gameplay for the originals is a bit more complex than the newer games, your stats and skills are more important that what you're used to. There's little to no hand-holding either, you must figure things out on your own so be warned. Turn-based combat may throw you at first and can be unforgiving at times, you need to take a more strategic and defensive stance in the originals and not just go in guns blazing,
If you can get past the widely different gameplay and get into them you may find the originals to be very enjoyable. I still very much enjoy Fallout 1 and 2 even though I've had them since they came out
Oh and give Tactics a try after you play 1 and 2, it can be quite fun as well.