I used U mobile for one month in december and I gave up.

The speeds are okay, much better and more stable than DiGi. I averaged around 1.5 Mbps in Sunway area. That is when you actually have a HSPA connection which you won't half the time. Sometimes just moving a few feet can cause your HSPA to drop and suddenly you're on Celcom's EDGE. And it takes a very long time to re-establish a connection back to U mobile.

My biggest gripe however is that there are a lot of strange black holes in the coverage. If you enter 10 feet into any shop in Pyramid you'll lose all connection to everything. Can't call out, can't receive, no internet, absolutely dead even though it shows 3 bars HSPA.

If you're using it as your home Internet then it should be fine. If you're putting it in your phone, please... Don't.