Marcos,
I have just finished putting the Pony clamps onto the bars. When you see the Axi and Pony on the bench they do look very similar. The paint finish on the Pony is not as good as I'd expected and thinner. This could however be that with being bright Orange any surface irregularities stand out over the dark green of the Axi.
Cosmetics to one side, when you really start to look the Pony are better. Castings are slightly smaller and crisper. The accuracy of machining is better, and particularly noticeable in the axis of thread and bar centre being truer/parallel. The threaded bar is also better with less play and a sharper cut.
In conclusion, if you are planning to use them a lot, keep a long time, or like the feel of quality they are worth the extra if getting them for the price I paid. If paying nearer the normal price I would give it second thoughts. What you end up with I think you will be happy.
Colin