Spectrum hasn't had issues with glitchiness in a long time as a rule of thumb. They did the first few years but those problems were addressed. That of course doesn't mean your radio isn't having problems OR the environment you are flying it doesn't have interference from something. As an example of environmental interference issues... The club I was a member of was right next to a large concert arena. The wireless security cameras and microphones they used... would cause a lot of interference if you got too close to the building. In addition, a faulty power transformer just outside of it did as well. Our club members lost signal every time they flew close by those areas. I've also heard a large equipment like oil rigs causing similar problems.
You can test for this... by doing a signal test. Place a model down and have someone observe it as you most the controls... you should be able to walk quite a distance before loosing reception and it gets sketchy. Now go to another location, preferably a very large field without anything around it and repeat the tests. While there will likely be minor differences in the distance you can walk away but they should be relatively close as long as there isn't a different in the terrain like hills etc. Most newer radios have a low power mode just for this type of testing, if yours does, it should be mentioned in the manual.
