Unless you are determined to have this Vixen (nudge-nudge) I think you'd be better off with the Tak.
As:
-It's quite readily available and a known quantity.
-It's mechanics are excellent, as are fit & finish.
-Its essentially part of a system with interchangeable 'bits' for different aplications. There are also a good number of second-hand bits available as well as third party gizmos made specifically for the TSA series.
-You can actually find out how much it costs here. I never have and never will by anything from the Vixen dealer as long as he prices things at $1500-$3000! Daft.
And last but not least (and assuming the price difference is not an issue):
-The TSA's optics are famous for their resolution and colour correction. If you have found a report that shows the Takahashi offering measurably or noticably, superior resolution, to the Vixen, that SHOULD be the end of it!
Its a no-brainer.