I checked out a company and spyfu told me they had 4300 PPC ads. turns out they have over 400,000 on google alone. WTF?!
Yeah, I thought it was a pretty cool site at first also. Turns out that their info is very inaccurate and outdated - waste of time.
Alot of those "spy" programs are using outdated data. Some companies do have huge keyword lists, but they also have agencies handling their accounts who get paid per click like Google does...
I have tried the spyfu pay membership and it blows. The other one that may be better (haven't tried it though) is keywordspy.com. Let me know if it's any good if you happen to give it a shot.