We've recently bought a couple of older Cisco Catalyst switches and replaced the Dell switches in the network.
First of all, the Cisco switches are more flexible and some of them even do Layer3 services, like BGP. So on top of the Catalyst 4006 for ExWest, we've got one of them in TeleCity and one in Mervue.
The changeover was done last week and things seem to be running pretty good. I'm just left with replacing the switches in remote sites like Abbeyknockmoy etc.
The reason for replacing the old switches is, that once in a while, when the VLan configuration is committed, the darn things just go daft and drop everything. All that is left then is to drive on site and powercycle the switch. Not something you really want to do, when the switch is 60-70 km's away.
Another switch that had to go is the Linksys Enterprise switch, because it's just a PAIN to having to find a Windows box, just to configure the Vlans. The switch's webinterface only works in IE and you can't configure Vlan's via SSH or telnet. How daft is that ?
Also our INEX Lan#2 peering are handed by the Catalyst in Dublin now. No major box needed there currently and we can upgrade as we go.