bigger and faster?
I think not. Foundry(like others) are years ahead of Juniper in the switching area. They have much bigger, much faster switches, and they have some really really big routers as well(3.2Tbps, 4 billion pps) which I'm sure can rival Juniper's biggest stuff.
Having just gone through a examination of Juniper switches their stuff falls short in many areas, biggest being ease of use, 10GbE and cost.
It won't even take 5 minutes of time to look at Juniper's portfolio of switching gear to see that they have a ways to go. They make great routers, and it makes sense for organizations that use their routers to use their switches, single vendor etc.. But best of breed in switching they are not(not that Foundry/Brocade is but they are better).
Even their firewalls are interesting. We're looking at Juniper firewalls as well and the general recommendation is to avoid the JunOS-based firewalls(SRX etc) and stick to the ScreenOS products as they have much better features still. I think Juniper has 4 separate firewall product lines at least..their product line up is almost as complicated as Cisco's.
Give me low cost, high density, power efficient 10GbaseT with an easy to use interface and advanced Ethernet based protocols for simple network management. There aren't many vendors that offer that combination..well I can only think of one, whom I've been using for the better part of the last decade.