I have only used my Celestron Ultima 2x 1 1/4 inch Barlow that I have had for many years and find it one of the best, sadly not made anymore but the TelVue 2x is of equivalent quality, at a price of course , and still available.
On the quality question all the cheap 2 and3x Barlow,s I have ever looked thru did not by a long shot equal an eyepiece that gives the same magnification , its like a vail over the view where as the good quality ( expense. ) Barlow,s don't.
On that when I want higher powers using my 2inch eyepiece, my TV 2 inch Powermate is the best. , tho really expensive. .
So my opinion is if you cant afford a TelVue or equivalent don't bother as you will be disappointed in the long run. , grab a nice TMB 6mm , this will be better.
My. 5c.
Brian.