I started on one about 9 years ago. First build, first plane. I wanted something slow and easy and it delivered. Built it with rudder only, on the right stick. Built another wing with ailerons for it's second year. The instructions are great! I had no problem building it. Converted to a tail dragger with steerable tail wheel. It has flown with a TT46pro- good match but doesn't need that much power. Has used a Saito 45, a bit underpowered. Also had the 65 Saito on the aileron/tail dragger version, super combo. The only "bad" thing about the Senior is it is susceptible to hanger rash moving it through the house due to its size.
The ARF version was popular here for a few years. The OS 70 four stroke seems the perfect match for it.
Can't go wrong with this one!