That's because it's budget equipment. From all of the reviews I've found it will do the job, but you're not getting performance out of it.
I'd still buy their gear, but I'm not trying to push miles into uncharted wilderness with my aircraft at this time. If I was flying more expensive gear, I'd want to make sure I had a more reliable video system.
It probably will. You won't know for sure if there is interference where you are flying that might cause you problems, but that is true with any gear. Based on what you mentioned you should be fine unless there is too much radio/electronic noise where you fly.