I have shipped one bike (Feb 2006) and one frame (July 2006) from England to the USA in the past 14 months. I DO recommend surface mail, and use it for ALL of my transactions in England.
There is no reason to believe that airmail is any safer than surface mail, in fact, with today's rushed airline schedules and pressure on airlines to cut costs and make more money after 9-11, there is good reason to EXPECT a frame to be MORE LIKELY to be damaged in airmail than in surface mail.
You always want to use royalmail because by using the national carrier you typically avoid horrendous customs clearance charges. It almost never saves money or time to use a private shipper for overseas transactions.
Many times of the year, a parcel (not bike, but parcel) sent via surface mail will likely go by airmail on a space-available basis. When you ship via surface mail, you either wait 5 working days or 5 weeks. It's a good idea to get the ship date from the seller so on the 6th day you can mark your calendar for the 5-week delay.
My costs to ship a bike : 88 pounds, it was a complete 24" bike in a rather large bikebox.
My costs to ship a frame : 45 pounds, it was heavily bubble wrapped with NO fork reinforcements (unfortunately), but arrived O.k.
- Don Gillies
San Diego, CA, USA