29er is king everywhere for general trail riding these day IMO. Everyone is different and many still prefer 27.5, but 29er is the new default. So unless you have a specific reason to go 27.5 (short, big in to jumps, etc) my advice would be to go with a 29er. I was a big wheel skeptic for a long time. Held my last 26 longer than I should have. Eventually went 27.5 and it was better in every way. Just got my first 29er and I really don't notice any downsides either. The geometry and suspension design will determine how long, quick turning, or playful a bike is more than simply wheel size. My 29er is actually shorter, quicker turning, and more playful than my last 27.5. And on top of that it has all the normal 29er advantages of being faster rolling and having better rollover too.