I wish the 328 had more interrupts. My biggest beef with it. I have a TTL circuit that updates one or more 193 counters so I don't have to use both available interrupts or run a tight loop just to keep up with an encoder and obviously it supports more than one encoder - as many as I care to lay down chips for. That's one reason I want to learn about CPLDs now, to see if I can implement my encoder counter into a CPLD and have it as one chip.