I've not looked through an XF so I can offer no insight into that comparison...
The Pentax XL and XW I have looked through and/or own and I would rank them both above the BO/TMP Planetaries in strictly technical terms (not comparing price). Not a wide gap but a gap regardless...
However, once you take price into consideration (at least at the time I bought mine buy 2 get 1 free) the BO/TMB was/is a very good performer for what I paid...
I have recently aquired both a TMB 6mm and an XF 12 mm (in the same transaction) so if weather permits this Saturday night I'll try to do a comparison in my 12" f5 dob. I don't have an Orion barlow, but I do have both a Meade #140 and a Televue 2x (not Powermate) to try.