I tried to do /stats me and my client crashed, ive heard that other people are crashing from /is trustlist but the load time for sf2.5 isnt that fast for me so id rather not test the others.
are you using any chat mod like tabbychat or chatflow? at least chatflow has some bug which can crash the client sometimes. it would help if you could post your minecraft crash log
If you are usign FTB Launcher the issue will be the mod ChatFlow. Go to the mods folder, locate the file ChatFlow.jar (may include version on name) and delete it. Please let us know if this fixed the issue.
When I switched to the MyM launcher I got rid of ChatFlow as well. Have not had issues with /stats me since then.