I've been using Reliance for last 3.5 years. Used different handsets: LG RD2030, Nokia6255, Nokia6265, Nokia3215 and now Classic (for a while!).
I never had any problem with network around 1.5 - 2 years ago, but I too face the problem of being Not-reachable, 2-ring then disconnect etc.
But it depends on where I am landing at, there are places where network is good (not accounting on the bars shown!), and some places have terrible network (may be 5-bars!). You may be at open space, but not been able to be connected and vice versa.
In short it's not the handset problem, but network issue.
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Nokia ****s! Dont purchase CDMA nokia handsets. I am finalizing some Moto handset soon!