Comment Don't Root it (Score 2, Insightful) 229
Virtually all the malware (and there is some drive by stuff happening) attacks people with rooted phones, so installing even a secure "ROM" is probably the worst thing you can do for security.
By looking for software that has gone through the common criteria (assuming that still exists or another similar certification process) you will have some reassurances that it was designed in a secure manner. I would also look for something using other government standards, like FIPS 140-2.