A major performance problem in VMware is saving virtual machines' state to disk. It's so slow that it makes me wonder how is it possible to write data to the disk so slowly, while causing the entire host system to crawl trying to read something tiny off the disk. It takes 2-10 minutes to save a Windows 2008 R2 guest with 1 - 1.5 GB of RAM to disk. For comparison this is how long it takes a well written tool to do the same (this log is from a disk backup utility that I wrote):
[ MB][ average] time
[ 1596][144 MB/s] 11.016 s
Compare: 11 seconds v.s. 2-10 minutes and you will see how well the vmware developers optimize their code. Also note that my tool doesn't disrupt other programs, only vmware does that. 
I have also used hyper-v on the same machine, and it takes only a few seconds to save the state of the same guests to disk. Performance on hyper-v is superior. For both disk and CPU intensive tasks and the guests ran just as fast as the host and even booted in half the time or less. The benefits of VMware are 32 bit display depth, drag and drop for files (which sometimes stops working), and USB redirection.
Note: right now I'm using 10.0.2 build-1744117, but version 9 is also affected from the slow save to disk.
@jessepool asked me to attach a log file, so here is the log file from Help, About. In it you can see that I resumed Ubuntu x64 guest first and then suspended it. It was relatively fast this time as I didn't do any tasks on the guest, but sometimes it takes a lot. Then I ran sync.exe and waited for it to complete (17 seconds for 1 GB). Then I resumed a Windows 2008 r2 x64 guest, let it run for a few seconds, run sync.exe on the host, to make sure no disk operations are pending, then click save state - it took about 5 seconds, then ran sync.exe again which took 88 seconds for 1.5 GB RAM on the guest. If I use the guest for actual work, it may take 5 minutes to save it's state to disk. While the data is written to disk, the host is terribly slow, so I can't use it for any tasks. So I usually run sync, wait for it to complete and continue with my work.