I've played a Martin C1 and hear it every week in my uke group. It was light and easy to play, but nowhere near as loud as my Kiwaya soprano and nowhere near as nicely made. Nowhere near there price, either, though I got mine used. I think the S1 is a nice instrument and because of your affection for Martins, I think you'd like it. Also, used they are a great deal and there are many open box opportunities as well. HPL is quite heavy and doesn't feel like wood, unless you need an expensive bomb proof uke, I'd steer clear of their X series, the Kiwaya eco series is a much better deal.