Used to use it years ago and really liked it. But I kind of got the impression everyone had abandoned it by now and moved on to MSN Messenger instead. No spyware issues that I know of; I believe it to be reputable.
I would get an msn account if I was you. I find it much better than ICQ....I used to get all sorts of messages on ICQ that were just spam..I am sure they have settings to eliminate it..but it got annoying and so to did the sound