I've used the 11 exclusively for over a year and just purchased the new maxed out version. I run a small restaurant chain and travel frequently. I use the MBA for all my business needs including presentations, spreadsheets, LogMeIn, etc. as well as personal usage for web surfing, photos, Net Flix streaming, etc. I have encountered no limitations at all for my needs and it is the only computer I own.
Do you hook it up to an external monitor at home though? How do you find typing on it or using the trackpad versus a larger computer like a 13" MBA or MBP?