there is a certain break-even point between glow and gas. That is at about 25cc. There are good 25cc+ gassers, and there still are some glow engines that perform well. Some manufacturers even spent years of hard work to make large glow engines work well (like OS).
Advantages? No, not realy. For a 26cc engine I personally would use a gas engine, and not glow, though I have the MVVS glow on the shelf. For 23cc, my ST2300 glow engine is a champ, but I would rather have electronic ignition on it, were it not, that methanol conducts current. So a little bit too much fuel will flood out the spark.
For power, methanol is the best, but at the expense of lots of fuel, and only a few quality oils will mix with it. These quality oils never obtained the quality levels that gas oils did. So for engine longevity and user friendliness, gas reigns above 26cc.
(example: don't try to start your big glow using the normal flip. You need to bump start it, or risk your fingers)
This uncontrolled moment of fuel ignition is exactly the reason to go to gas in larger engines.
Gas engines have smoother power and lower vibration levels than glow engines of equal capacity. Once run in, less slime to wipe off, and yes, A long learning curve before you and your gas engine get along. A gas engine is no easy push-over.