I have used the Ohana’s for racing up to 1/2 IM. They work great for me, I like them alot. I do not train in them on a regular basis as I use cheaper trainers.
The Mayflies are only rated to like 100k of useful life. So they will be for racing. They are VERY lite at like 5.4 ounces. The Ohana’s aren’t much heavier at like 8 oz or so.
I’ll be curious as to how the Ohana’s work with training and running off-road. I only run 2-3 days per week for about 40-50 minutes each time.