Read the thread (in this forum) about the YS 170DZ CDI. It is very hard to beat the simplicity and ease of operation of the 2-stroke engine which does not require 30% nitro. If you are flying in the lower classes there is not the need for the extra power of the YS 170, in my opinion, and the most important aspect of pattern is the ability to practice effectively without equipment issues. The improvements in electric propulsion systems are making glo engines obsolete in pattern (sadly).