If you are otherwise really happy to keep the car, then I would go for a new vw engine with warranty. If you have lost heart, then go for cheapest option & get rid.
Make sure its genuine with written warranty. At least you know its all new and not ripped out from some scrap yard. I had a recon engine from main dealers, years ago when I was young
, and that was'nt built correctly.
Don't think it will add much to value, as everybody would expect a working engine, and might be scared off by the trouble you have had...that's cars for you