If you are looking for affordability, versitility, and overall ease of use, CineHarps (not the original CineHarp) by CineSamples is rather remarkable. One of my favorite and most used purchases of this year. I used to be a hardcore Spitfire Harp user but CineHarps replaced it by 100%.
It's not a purist type of library so if you are wanting to program note for note glissandi, Spitfire or OT's Harp has that type of articulation available. However, everything else packed into this library was well worth the price. I know I review libraries and have received NFR's from many companies. However, this was an out of pocket expense and I can truly say, as an avid user of it, that it's one of the best on the market.
Cheers,
Chris