I've flown a Garden Horizontal; what a strange affair.
Firstly, you can't have the wheels down without flaps.
Secondly, to raise the gear and hence flaps one has to wind a lever on top of a tube between the seats. It must have been me but I couldn't wind with my right arm without pulling a pushing the yoke with my left.
Then there's the performance. Or lack. A number of my aircraft have had better performance without a CS prop and retractable gear. I used to fly a MiniCab which you can see in the Horizon and that was a more pleasurable experience.
Considering some of the whacky things I've owned I should be the last to comment, but Horizon vs PA28RT? C'mmon.
SGC