Still not pleased with FCP GFX titles...if you take a jpeg and tilt it the edges go jagged saw tooth style. I thought FCP 5.1 was supposed to rid the application of this problem...
Make sure you use Title 3D and NOT the legacy title generators.
Always view only on a video monitor, not the computer monitor.
Also, it is poor form to use JPGs. Use a lossless format: PICT, PSD, PNG or the like.