If you are not participating in M.U., stay with version 5.
It's stable, works fast and reliably.
If you are going to report M.U. data, upgrade to the latest v6.1.2. Understand v6 is slower in many regards, and more buggy than 5. ERx works good though.
I agree with what others have said. But stay with what is working well for you. Upgrade only when you NEED to upgrade, not just for the sake of upgrading.
that being said, 9 providers under the Medicare MU could yield quite a lot of money to pay for the IT time to institute the change. You would get a lot more if you qualified for Medicaid MU. I understand the reasons why many are not participating in MU. I'm just saying that if MU is ever in your future, do it now while the money is there and use the incentives to reinvest in the technology base of your offices. Just food for thought.