Personally I think Marsupial Gear did a really nice job on these radio pouches. I went with the larger one because I have one of those extended High Capacity Li-Ion Batteries for my Baofeng, which is about an inch or two taller than the battery packs that initially come with radios. The pouch would also work nicely with my Garmin GPSmap 62s, and in theory, it would offer my GPS more scuff protection than the smaller pouch could.
I have not used it in the field but my Garmin fits great.
I recently purchased an Ultralight upland system and needed a pouch for my Garmin 320. The pouch fits the Garmin perfectly and keeps it out of the way but easily accessible. I originally intended to use the system without the yoke but found out that I had to tighten the belt so tight that it was uncomfortable to keep it from slipping down (I have the standard old man build, gut with no ***). Using the yoke the system works great for me. I removed both water bottle holders and added the radio pouch and a large zippered pouch and just carry one bottle of water in the bird bag bag. very comfortable and much cooler than the upland vest I have used for years. Great quality build.
Holds my garmin radio just fine
The Marsupial Gear small radio pouch is a great design. I purchased it for a GPS unit, and it turns out my unit fits a little too snug in the small pouch, but this is still an awesome pouch that I will use for a 2-way radio instead now.