I've found the Uhlmann/Allstar synthetic gloves do tend to last longer than the less expensive synthetic gloves. If you put together an order from
Fechtsport-Langenkamp that's large enough to make the shipping costs work (not hard if you stock up on point parts & wires for the season), you'll only have to spend about $25 for the glove.
If you want the best durability, a good leather glove will outlast a synthetic glove if you take care of it. The rub is, it's much easier to just toss the synthetic glove in the wash than to take good care of a leather glove (hand-washing with saddle soap and oiling with some regularity).