Unreliable how?
The AR610 isn't exactly a high-end RX, but spectrum gear is typically very good. If something isn't functioning right due to setup, swapping out the RX won't help. If it's failing for defect, Horizon is usually pretty good about supporting their products -- you pay more, but in return you actually get support.
For alternatives, I've had great success with the OrangeRx 615X recievers. they're running on about 1/4 of my fleet, with the older DSM2 615's running on most of the remainders. plenty of range and cheap.
Plenty of people recommend the LemonRX RX's as well. DSMX and DSM2 versions re similarly priced between Orange and Lemon, and many who have used both report similar performance.
I can say, beware of clones-of-clones. Orange and Lemon RX's are Spektrum clones, but function well, however no-name Spektrum clones and clones of Lemon and Orange RX's are on the market and underperform. I'd avoid Ebay for RX's -- no way to verify they're real before it's too late. I'd recommend buying spectrum from reputable hobby shops, or buy lemon/orange RX's from the source -- lemon from lemonRX.com and Orange from Hobbyking.