I cannot comment on Peak but we had to make the same choice a few years back in Tai Tam. We chose Sunshine because I liked the style of teaching. Still fairly traditional but very thorough and loving. My oldest went on to ESF and was very well prepared, was able to read and write a little bit and had no problems adjusting to ESF. Woodlands here is Montessori, and I am not huge fan of mixed class rooms (they're mixed enough as it is in my opinion) and other aspects of Montessori (I've been through Montessori high school and my husband through Montessori Primary). I don't think Peak is Montessori though. Another thing, I wanted full days for my oldest back then, but full days at Woodlands is until 4 (only 2.30/2.40 pm at Sunshine which I found much more suitable). Plus in the end it was even more expensive as well. Also, ESF visits Sunshine House prior to the Y1 interviews but not Woodlands (as least not in our catchment), so all (future) things considering, that's how we came to our final choice.
I do realize your looking at Peak but I still hope it gives you some insights, and things that we considered in that choice (knowing people that were happy at both schools).