I have placed an order for RB5009 to replace my RB3011. [...] but will it be worth the upgrade?
[...]
I also have both RB3011 and RB5009 on 2 Internet connection. For "simple" PPPoE setup the RB5009 is very stable for months now, but my primary link is still on RB3011 on 6.4x ROS
The RB3011 is still a very capable good box.
The RB3011 has a display which is handy... The nice part about whether its "worth the upgrade", will be your time – use the RB5009 to fiddle with V7 until your happy with it there. Then, switch the RB5009 as your main router, when ready. (And, yes you'd want to run 7.1.3, or 7.2rc4, not the 7.0.3 it comes with it)
I use
VRRP a lot. Since you'd have
roughly similar routers, you can could then add VRRP to your configuration to use both for redundancy if you want. V7 even
sync support connection tracking for VRRP to make that a backup router work even better.
While I think I a
pair of RB5009 in just 1U rackspace is kinda handy concept for a redundant setup (e.g. if you upgrade/reboot a router, internet doesn't go down). You already have an RB3011, that seems like it make a fine "backup" one day here.