Just did my 2 month stint in Bali for this year.
3G in 2015 is much better than 2014. About 2x faster.
2014 a good speed was around 3-4Mbps
2015 a good speed is around 5-8Mbps
Upload/Download ratio can vary wildly, and 3G can drop out often.
It’s over congested in most popular places so you can ignore the above speeds in practical circumstances. Ubud central was dropping out to Edge speeds very often, (though Penestanan where I stayed a week scored a consistent and reliable 5-6Mbps). Canggu (Batu Balong beach) was unusable, always on Edge 50kbps.
Many places are on fiber Internet this year, I was getting 3-8Mbps in many restaurants and even a few homestays.
All speeds are testing to servers within Indo, expect much less if you are skyping to further flung places (like 4x slower is not uncommon). In general the pipes leading out of Indo have improved for 2015, IMO we’re seeing 2x the International bandwidth as 2014 which apparently was an atrocious year.