I wonder if 1gig for the graphics card will suffice. 2 seem better. Until recently, I had a GTX 650 with 1 gig. I could even play GTA Online "okay-ish" but only on lower settings, and you know, when driving too fast or after some time, you could note the strain. I mean with the lower settings the memory was already hitting 1k, and if it was too much, you'd see pieces of the map just vanish or not load fast enough.
For some weird reason, I recently still got it with a GTX 745 and 4 GB. I'm not a tech expert anymore, could have other reasons. CPU should be fine, and 8GB Ram too.
ANYWAY, TO THE QUESTION AT HAND:
1) If you can play it, then it's worth the money on PC (imo)
2) ... also consider the mod potential, for all that funny stuff alone it's worth the money I think. You benefit long-term though, as obviously mods come out over time, and the more complex ones need time until someone tries to come up with the idea and then realize it. And then perfect it and fix bugs.
If you are into the general FO lore and setting, can play this one and don't mind some of the new additions made to 4 (dat dialogue option limitation doe), then you can spend many hours, and extend that with mods again. Already running notable mods I don't want to miss and the GECK isn't even out yet, which means the real magic will happen once it is out.
Granted, the hype went down for me, I finished the MQ (take your time, explore, do sidequests, don't rush it, imo), I still have a lot to do in the game but currently focus on other things. Still...
In short: I think it is worth it. Even if you critically judge the main quest itself. When in doubt or yet not really sure if playable, simply wait. It's not like it's running away from you.