About 3-4 months back Reliance wimax had this upload problem and users were not able to send any e-mails atall and were not able to upload anything but that issue has now been sorted and there are a lot of reliance wimax users who are happy with their service but like every other ISP in India reliance wimax will give you trouble as well coz none of our ISP's are capable of providing a no downtime broadband connection.
Reliance wimax has one known issue right now and that is getting an ip assigned is a problem when you try to connect and it may some times take a long long time before you get an ip assigned.
Its still better then a lot of other ISP's I would say.
If you have got airtel broadband available where you live I would say go for it and if not then I guess you are not left with many options except for reliance wimax and tata wimax and I have had my share of problems with tata wimax and I would not recomend tata wimax in this life time.
Do let us know what connection you got and a little review of how it went if its not too much of a hassel for you
Thanks