Using RFID tags in *markets is a potentially lucrative, but inherently imperfect (if not bad) application - pressure for low cost, requirement for long distance sensing, high tag density per area,high RF noise, unskilled personnell, goldminers among the suppliers (gluing together bad systems)... There are areas where this technology undoubtely belongs (don't you have an RFID-based worktime logging/access system in your company? If not and 10+ employees, get one!).

To answer the original question, I doubt there are too many people with experience with both manufacturers. You usuallystick to one of them, buying starterkits etc, then using both the base station and tag ICs of the same manufacturer - in the hope of compatibility (although it should work with the other, too). We are using the Temic's (now Atmel) U2270, together with TK5551/5561.

The base station needs careful PCB design, properly decoupled supply, different from digital supply, short paths, ground planes, single-point ground to digital ground connection etc.; but we have nothing more than the circuit from the appnote and it works OK (but we had problems with the tags themselves...). Oh and be careful with the capacitors parallel to the antenna coil, there is ~100Vpp, and nonlinearity of certain ceramics makes problems... Check it out.

Jan Wacwek