I have the 5435 and I find it to be perfect for my needs. Currently its powering a set of Hertz Audio Space 6s through a Audison SRx 4. They sound amazing.
The deck features are enough to keep the novice car audio guy very happy. All your basic controls are there, you can also use it as a "GPS", but its not really GPS you map out your route on eclipses website and then DL it to a CD and then upload it to the deck. then it tells you where to go and you tell it when you get to each check point. Its kinda cool.
My only complaints are the volume and track dials, they are not that accurate, meaning sometimes when you turn the dial the volume will increase more than you want. from 0-50 it increases by 2 with one click of the dial, but sometimes it goes up by 4. Same with the track dial, you want to go ahead one track but it goes ahead by two, its not a big deal but it can be anoying.
I still give it two thubs up. But if you can afford the 5445 or better Id go for it, the memory card slot is a very nice feature. Imagine having one or two 1gig cards with al yor music on them. Would be pretty sweet. not to mention the fact that when your buddy gets in the car and says, "I have this great CD" you can say, "pop it in so I can hear it" then copy it onto your memory card! pretty dam cool if you ask me.
well theres my two cents.