i am finding the waves nls to be excellent, owned it for a long time and only recently started messing around with it, liking it a lot, use it all the time, also really like the ssl (different animal) as the dude above i put it first inline.
with the nls you have buss and channel versions each with 3 different consoles, a ssl 4000g, a neve 5116s and an emi tg 12345 mk4 i believe, and the way it works is quite good. in studio one apart from using them on all the tracks and busses i have started opening up the inputs and place an instance there so
anything coming in goes through it first before hitting the tracks, fx bins/busses etc, has made a huge difference, wouldn't do it any other way now, and in conjunction with the console shapper and/or ctc1-pro, it sounds awesome