According to user reports/tests (especially by AWilder), the LTM version is incredibly sharp with high resolution in the center and somewhat softer in the corners wide open.
I like mine very much for its compact size and fine images. It's not quite as special as the ZM C Sonnar, to be sure. The C Sonnar at 2.8 has much more cream-n-dream than the Rollei LTM Sonnar. The color rendering of the latter is a little more reddish than the ZM line. It shines for B&W and is especially suited to portraits, but I use it for landscapes and items of interest.
You should be able to pick one up for around US$400, making it competitive with a Rokkor 40/2 or Summicron-C. Which to choose is up to you. The tests that Alan did showed that the Rollei outresolves the Summicron-C on center (it equals the Summicron 50), while being less sharp in the extreme corners. Sonnar-ish, in other words.
I have some fine examples of photos with this lens but can't upload anything till my container arrives from Taipei...