I have the 2" ED GSO and I am quite impressed with it. Works well with all my ep's and I haven't noticed any adverse effects from it. I should mention that I don't own high end ep's and the like so I am not influence by naglers and others so I don't know what I am missing and therefore don't see it
. If your like me, a budget conscious observer who has never used high end ep's then I think you will be very impressed with this barlow. If you do use high end ep's then you'll probably still be impressed as some of my friends were. BTW I have compaired the GSO to the Orion Shorty Plus (A friends) and I must admit I prefered the GSO. Take from this what you like, but I hope it has helped you
Leon