If your primary concern is reliability then do as Boomerang suggested and go with electric.
Personally I would install glow engines all around, BUT I'm a small glow engine type and have operated both of the engines you mention. The fact that you are even asking questions about these particular engines tells me you may not be too familiar with them. With this in mind I believe that you are likely to have continuing problems for quite awhile and will have numerous inflight engine failures. Small glow engine are not impossible to get to run reliably but they do take some practice, patience and tinkering.
The question comes down to this: How much of a challenge are you willing to take on? If you are the "I can make ANY engine run right" type, then go for it. However if you are the "I like OS engines because they are easy to run" type, then go electric.