Just to update this a little, the prices went up marginally at the beginning of the year, because of the 1% increase in the IVA/VAT tax rate. For example 503.34 pesos a month in the non-border areas.
I do indeed get through more that 3GB a month, and you can't just start a fresh month, you have to wait for the 30 days to expire before you can get high speeds again. I switch to a second sim during the month instead.
Capacity is fine now, generally get 1-2Mb/s most of the time, maybe 500kb/s at really peak times, and sustained 2.4Mb/s at really off-peak times. Which is why 3GB doesn't last long at all.
