I've never had problems setting up multiple VLANs on a link between Cisco, HP, Dell switches, IBM mainframes, VMWare servers, 3COM/Nortel, Polycom Phones, Linux servers, etc. If both ends supported 802.1q, it just worked, if the admin read the manual for both pieces of gear and knew how to troubleshoot problems. Sure, one vendor can be nice a lot of the time - even cheaper once support costs are factored in. But making VLANs work between different vendor's equipment is a pretty basic networking skill. So I'm kind of astonished at the "sell what you have and buy new from one vendor" responses. I've not used the specific Dell switches mentioned, but I've used others and have plenty of opinions on the management interface of them. But for a wiring closet or top of rack switch, I can't say that I would suggest to replace them with something new just because I wanted a different management interface (that said, I very well might write some scripts to manage the uglier interfaces).