i disagree with 90% of that, I've got three 60s and two 50s (two 30s but thats not part of this equation) and they are all equally consummative on fuel, all require about the same building techniques (with the exception of the X-Cell but the 45 sized X-Cell is equal to their 60s) and power to weight, most 60's have more reserve power then the 50s with the ability to pull more pitch under demand without loosing head speed or engine RPM (they have more torque power). i do agree the cost of repair is SLIGHTLY higher between birds of the same MFGs but the ease of flying a 60 compared to a 50 is more to the liking of someone just learning. 60s and 90s are considerably more stable for a new person learning curve hands down and the higher cost of repairs are offset by the less frequency of crashes due to a more stable learning platform.

kc