Barlows or Powermates?

Saw a few reviews comparing the two. Is there anyone who can weigh in on which to buy?

I think it depends what eyepieces you want to use
with it. If you are using long focal length
eyepieces, like a 26mm 1.25" or a 35mm 2" then
the Powermate will give you less darkening around
the field edges. But for shorter focus
eyepieces the simpler Barlow will be fine.

For planetary viewing, or some critical
high power viewing, I might prefer a
Barlow, since there are fewer lenses and
less to go wrong.

Peter,
I agree with John. I have both and tend to use the powermates with the longer focal length eyepieces. For anything under 12 to 15mm I always go with a good Barlow.
Clear Skies, Bill

The physical length of Powermates is a mild minus in my opinion, especially when used with a binoviewer, but otherwise they're superb optically. For regular barlows I would go with the Celstron Ultima 2X every time - I use this and the 2.5x Powermate and find both extremely useful.