Honeypots can be very good at alerting too. I consider them better than IDS because they hardly generate any false positives or false negatives.
Honeypots, perhaps do not provide many false pos/negs but they are much more limited in scope than an IDS. They catch very specific types of events while IDS devices capture most, if not, all varieties.

Reactive IDS devices (IPS) or whatever name you slap to them are intended to be defense mechanisms. The problem is that I have yet to see someone deploy an IPS solution with great success. No one wants to impact the business adversly with a bad IPS rule so most are configured so lightly they barely make a difference.

Another 2 cents...

--TH13