I think the only issue I have had in the past 8 years I have been working on Peregrine products involves the drop in level of quality support after HP bought them.  It has been terrible.  HP says they are 'fixing things'... we will see.

On the other hand, I also have been trained in BMC Remedy and have had some exposure to other tools.. Service Center is by far the most powerful tool around in my opinion.

What happens when Service Desk and Service Center are merged in release 7.0 should be interesting...

That merging has already been released...

It's basically SC 6.3, and most of the additions beyond 6.2 are enhancements to support functions that SM had that SC did not.  Some of those enhancements are pretty cool stuff.