Reliance Wimax Broadband service is by far the best service provider I have used. I have used Local service providers(which are basically reseller of sify service) and Adsl service from another telecom company. Both the cases I have had issues with the medium of connection ...i.e cable.
Reliance wimax being wireless never disconnects. It gives speed as promised. Mine is 400 kbps and they give me 50 KBps download speed(400/8 = 50 KBps). They are expensive and do not have any plans in the low range category. I have used skype, torrents etc, etc and download about 30 --40 GB per month and it works like a breeze.
Yes occasionally sometime the tower gives problems but it could be due to various reasons like no power situation. Point to keep in mind: For getting Reliance wimax you should be lucky enough that there is no obstruction between your antenna and the signal tower also note that the signal strength should be above 20 & it should show up as Green.
Also note if the Service is down due to reliance tower issues or their own system maintenance issues. Let them know by calling up customer care and when the bill comes ask them to discount the bill by appropriate pro-rata charges.
Cover you antenna during the rains.