Nortel 455x Series Comparable Cisco Model

I used so far Nortel switches like Nortel 4550T-PWR, recently few of them died and since they have only 1 year of warranty i'm looking into other options.

To Nortel is this Cisco comparable model Catalyst 3750 (p/n: WS-C3750-48TS-S) or this Catalyst 3560 48 10/100 + 4 SFP IPB Image(p/n: WS-C3560-48TS-S) ? If is some other model please let me know, and i got around 20 nortel switches 2xxx, 4xxx and 5xxx series and at at least once a year one dies is that normal? They are properly installed in server rooms so there is no overheat issue.

And how much warranty Cisco gives on their switches which are comparable to 4xxx and 5xxx series of Nortel.