Hey Patrick,
If I recall, Tim's survey numbers had Factory 3 more prevalent than Factory 25 by a fair margin (nearly 3-1), comparing the Broadleaf-class cards, only. Anon Factory 3 Recruits are as tough, if not tougher than their Broadleaf counterparts. You have a number of catchers to choose from there, and really need one of each for completeness ...
)
Hardest thing you'll find on the Anon Factory 3's is grade sensitivity. Some of the Broadleaf class cards have fared OK , but the Recruits have generally not done so well. Finding anything in SGC 50/PSA 4 will be a real challenge.
Downside is that the sample size of all of the cards is relatively small, all things considered. I'd wouldn't put too much stock in very specific numbers, but feel that the trends and general observations hold out very well.
--
Mike