if you are not comfortable hacking/tweaking your TyTN, then leave it for now.
this release is UNSUPPORTED by your carrier, so this forum is the ONLY place to get bugfixes. there are some issues (read the wiki), but they are minor IMHO. However, as this ROM is based upon a beta WM6 ROM there surely are other "issues" to be discovered.
if you are willing to devote the time and energy to hacking/tweaking and will not freak out at every little issue (and if you MUST have the latest and greatest) then go ahead and upgrade.
you can always downgrade if necessary...
Q: Will you still release a version based on the original Rom (from your unnamed source).
A: WMXL v0.20 uses my original Base Rom. Please note that the Vanilla Rom is derived from the same Base Rom as I have been using. The big difference is that I spent a lot of time sifting through the Rom files sorting what to delete whereas the Vanilla Rom, while good, has had a little too much trimmed off in some areas while junk has been left standing in others. Another difference is that I have changed a few files in WMXL v0.20 so that it can support Cingular's PTT.