Treo 650 or Siemens SX 66

I’m about the upgrade my cell phone and trade my Nok 3650 camera phone in for a nextgen phone. Everyone says the Treo 650 is the hot phone, however the Siemens SX 66 looks good too, maybe better than the Treo because it also has wi-fi and is quad band. Both have cameras, QWERTY keyboards, sophisticated e-mail, and real web browsers. The Siemens, gasp, runs a version of Windows, which makes me a little leery about viruses, etc, while the Treo is Palm.

Any gurus out there with advice on which is best?