There are a large number of opamps in the so-called "rail-to-rail" category: these either have an input common-mode range that approaches or exceeds the power supply rails, or they have an output range that approaches the power supply rails.

I'm aware that selecting the RRI/RRO requirement restricts yourself to a smaller selection of opamps, that will cost somewhat more (but not greatly so).

But are there other reasons to be careful w/r/t RRI/RRO opamps? I had a former coworker who avoided them like the plague and I want to know what to watch out for. **In particular, are there any performance specs (gain-bandwidth, slew-rate, etc.) that degrade as the input and/or output approach the supply rails?**