The truth? Go with a PS2. Maybe not immediately; Lucasarts is still getting its feet wet in the next-gen console market.
They have yet to show a real commitment to the Dreamcast. Proof, you ask? There are NO games slated for release on the Dreamcast that are NOT PORTS. Racer is a straight PC port; JPB will only add higher resolution textures and models to existing design. Word has it that they'll skip any original designs for DC and go straight to PS2. Starfighter is the proof.
We went to LEC with proposals for a Dreamcast version of TPM with added levels, high-resolution skinned models etc. etc. in April of 1999, and they weren't at all interested. Even during the summer of 99, when the PSX version was still unreleased, we continued to pester them that a DC version would be quite neat, to no avail.
My personal opinion is that LEC underestimated the Dreamcast, realized that it WAS a good platform right before US release, then made a few attempts to cash in on it, but it was too late. Now, as much as I love the DC, it will probably be dead this time next year.