I just released Framaroot, it now include an action choice after executing root exploit :
- Install Superuser
- Install SuperSU
By default Install Superuser is selected.
For those who have noticed freeze and slow device after root, I can't help you if you don't take more details about the problem.
I suspected version of Superuser but its only an assumption and I changed version used in Framaroot. Now you can select SuperSU, I suggest to try both and see if it continue to froze your phone.
If it persist, please guys give more details when it happen (ie: ps output to see cpu usage or output of top command and log in /dev/log/ and /proc/kmsg) ... the omniscience does not belong to the men