Cisco ACE may not have been a good fit for you & your shop, but all three pairs of our ACE20 have been great in our environment.
I know the hardware bug you mentioned, and it's indeed very aggravating that there's nothing anyone can do about it, but it can happen to any vendor, and not just Cisco.
The fact that ACE uses the same MQC structure that's used on routers makes it extremely easy for training & management.
Took me less than 30 min to teach a new guy, who's never worked on ACE before.
Once again, this works for us, but probably not for you, or those who have a different requirement & environment.
I do agree though, that we'll probably go w/ either F5, or Citrix when it's time to replace our ACE20.
If you have a need to support the kind of applications that require the best in every category, then you have to go w/ the best.
Who doesn't want a network that performs at the highest level?
However, it comes w/ a price - multiple vendors, contracts, support organizations & flows, extra training, etc.
I'm well aware that some of Cisco's stuff either under-performs, or are just ridiculous...we've yelled at our account teams & BU's on numerous occasions.
However, for us, having 90% of stuff on Cisco makes sense - one vendor to deal with, one number to call for support, and you just go to one event (Networkers/Cisco Live), and you get to take training in whatever technology that interests you.
Also, if your budget allows it, you can sign up for Advanced Service's NOS, which has all sorts of benefits that are very difficult to get when you have 10 different vendors on your network.