Im voting Brocade on this one.
The ISP I work for uses a lot of Brocade stuff, primarily the 4100 series I believe. They seem quite a good unit, I cant remember a time at all
when weve had a SAN issue caused by a bug, or failure of one of the SAN switches (Ive been at this ISP for about 20 months). That scores well, especially when you are on the (level 2) helpdesk.
If it aint broke, dont fix it I say.
Im not privy to the pricing of the Brocade stuff, but I do believe you have to licence them based on the number of ports you want to use. This may be the deciding factor if you are looking to reduce SAN costs, and the Brocades are more expensive to license than another vendor.
But as I said above, if the Brocades work reliably, why move away. Thats not to say that another vendor wouldnt be as or more reliable. I say that based purely on experience, but with nothing to compare either - Im still voting Brocade though.