I currently commute with BMC Alpenchallenge AC02 with the Alfine 8 speed, roughly 10 miles a day round trip. For over a year now, my IGH has been nothing short of stellar for these reasons:

• Fast gear change ability, I mean really fast. The Rapid Fire Shimano is very..well...rapid.
• No grease to worry about staining my work clothes
• Easiest bike I've ever owned to maintain, which is practically none.
• Fast enough to get around town, but also great for longer 30 mile casual bike rides. Anything longer than 30 miles I get my carbon fiber road bike out.

I haven't had any gear problems, as noted by others, no skips, slips or weird dragging. I also haven't had any flats in over 3,000 miles of riding (I know crazy!) on the IGH, so I can't attest to changing tires on the road with an IGH. I have had to replace the tires due to normal wear, that was a slight PITA, but nothing so hard that I couldn't do it myself. Overall, I'm very happy with choosing an IGH bike.