Oh, boy聴tough question. Buying a kayak is more like buying shoes than buying, say, a Gore-Tex jacket or backpacking stove. Fit matters 聴- a lot 聴- as do personal preferences in terms of a boat’s layout, how it handles (maneuverable versus straight-tracking) and its stability (some boats seem unstable at first, but actually are hard to roll; others feel real solid until they start to go over). Plus, a boat is a major investment, so there’s understandable angst over a buying decision.
Still, I’ll offer a few suggestions. For one thing, my understanding of the Synergy ($2,599) is that it’s for small-to-medium paddlers, someone more like me (five-foot-nine, 155 pounds) than you. You might look into the Synergy HV, instead. Either way, it’s a performance-oriented touring boat, recommended for intermediate to advanced paddlers (read: less stable than a beginner’s boat).
The Current Designs Sirocco ($1,200) is a roto-molded “plastic” boat, not hand-formed fiberglass like the Synergy. So it costs less, and is a little heavier. My understanding is that it’s more mass-market than the Synergy, meaning more stable. But it’s a great all-around boat. Corona’s Perception ($1,299) is another roto-molded boat, closer to the Synergy than the Sirocco in performance and handling. Lastly, the Cortez ($1,400) is another high-performance touring boat. In particular its hard chine (lengthwise edge along the lower portion of the hull) will make it feel tippy at first, although stability will increase as it rolls.
So if you’re really just starting out, I’d recommend the Sirocco; if you want something a little more daring, any of the other three would work well.
At this point I need to throw the question back to you: What do YOU like? You say you’ve tried a number of models, and that’s the best way to shop. Set up some general parameters, in terms of price and size, then get in some boats. All the boats mentioned here are from extremely reputable companies, so quality is not an issue. It’s what works best for you. Keep paddling, and when you find the right one, I think you’ll know it.