I know this is an old thread, but I picked up a set of the R341's recently and thought it might be helpful to add some photos of the differences between the R100/200 vs. R340/341 levers. I won't describe the 100/200 series, since they've been around for a while and it's easy to find photos of them as well as first hand reports.

I could tell from the QBP photo the R341 had a funky ergo bend in the lever, but it didn't tell the whole story. The lever bodies are a bit bulkier and blockier in shape, like Tektro is trying to approximate the shape of brifters. The view from the cockpit shows that the new lever has a slight hourglass shape, though the body is the same diameter in the grip area as the R100.
First the R100A, then the R341:



The lever bodies are actually the same size, but I didn't maintain the camera's distance from them between photos.

The major difference is in the lever, the R341 has a bend to the outside that makes it easier to get the lever further out under your fingers (you can actually see the tip of the lever in the photo above.) The bend is exaggerated a bit in the photo below because I have them on a set of randonneur bars which angle out slightly.
R100A on top, R341 below:





Looks pretty weird from the front, but I really like the way they feel - the outward bend definitely does what it's supposed to. From the side they're relatively normal looking:



I hope this helps those who need to choose between them.