This is Gibson's current standard in pickups. They are wound a little hotter than vintage with some change in the 50s-70s formula that gives them a little extra upper mid. The coils are potted, so are the covers if your guitar comes with covered 490s. The neck pickup has an Alnico 2 magnet.
I am not a huge fan of the 490T and I loathe the 498T (soooooo nasal), however the 490R neck pickup sounds good as a hot neck with good articulation as well as doing a passable job in the bridge position with a low-side-of-vintage-output bucker at the neck.
All in all these are nothing to write home about, but they do provide serviceable sounds for most genres of music. Considering they are a stock Gibson option on a lot of affordable models they are impressive and can sound better than a Gibson 57 classic in some instruments for certain applications.
That said, there are some pretty affordable aftermarket humbuckers that own the 490 pickups...