I'm surprised to read 'heavy' used as a description. I have a couple, and they're pretty lightweight compared to other synthetic jerseys I have. My complaint is that they develop the funk typical of synthetic fabrics, which makes it a little less pleasant to hang out in the taproom afterwards. I'd love to have a merino version, but my wallet cringes at the idea. Like mattnmtns, I got one of mine on sale at REI in combination with a rebate, and the other I bought directly from them at Outerbike (50% off). They dry pretty well in my experience, but I'm in a semi-arid climate. They also have mesh panels on the side, so they breath pretty well.
I've debated just wandering through the local Murdoch's ranch supply and seeing what they have for cheap western shirts. I can't go back to wearing 3/4 sleeve jerseys in summer again.
Honestly, one of my favorite shirts is a Cloudveil fly fishing shirt made with stretch-woven softshell fabric (their own, unfortunately, after they moved away from Schoeller). The fabric is jacket-weight, so it's not light, but it's one of my favorite pieces of gear. It's an ugly light green, and isn't all that flattering, but it's comfortable in rain or shine, in temps from the 50s to the 90s. I floated the Grand Canyon a few years ago and wore it pretty much every day. It works great for big mountain rides, too.