We are currently running 6.4r4.1 on our SA-4500 which has been very stable. I am debating whether to go to 6.5 or 7.0. Any thoughts or concerns with upgrading to one vs. the other?
The recommended release is still 6.5.
I've noticed that Juniper is often slow when it comes to getting their recommended release in-line with the latest code trains. 7.0 is now at R4, so I would think it's mostly stable by now.
What I usually recommend is that if there is a feature in 7.0 that you really need, then you will probably be OK since like I said, they're up to R4 now. However, if you don't need any of the shiny-fancy-whiz-bang stuff in 7.0, it's usually best to stick with the recommended release.
I'm running 6.5 in production on a HA pair of SA-4500s, and I have a testing environment running 7.0.