I don't anyone wants to admit to having any experience with a Maloney. All kidding aside, they were low on power and hard to start without an electric starter and they generally ran poorly.
A few people ran them, but for the most part the modelling public took a look, kept their money and the Maloneys went away. The 100 was the worst-terrible was a good description. The 125 was a little better, but still could not measure up to any other small gas engine conversion that I know of.

If you like playing around with engines, love to tinker and have a high tolerance for frustation, play around with them. I would not recommend you put them on a plane you want to fly regularly.

Sorry I'm so negative, but the reason you don't see them today is they didn't measure up.