17T4 or 21/14XL?

Which combination should I keep?

(2") Nagler 17T4 with 2X PowerMate (really Big Barlow/Panoptic Interface)
(1.25") Pentax 21 and 14XL with 2X Ultima Barlow

Each combo is about $450-475 on AM, surprisingly close :S

Any unique insights?

-- William

Tough call William! :S
Do you find the 21mm to work well? I have not used one of those, but I have heard they have spherical aberration, is that true?
The 14mm is a nice EP. The Ultima Barlow if a pretty good piece.
The 17mm T-4 is a great EP and the Big Barlow I also find to be excellent. The two together work well, but only give you two focal lengths where the XLs give you four.
Now if the 21mm is not as clean edge wise, then I would go for the 17mm Nagler, but if the 21mm is clean to the edge, I would be tempted to keep the XLs.
I have the 17mm T-4 and the 10.5mm and 7mm XLs and I like them all.