While TRX may be more expensive, they back up their product with consistent education and program design. I have called and emailed them on numerous occasions and the customer service has been outstanding.
I am a firm believer in the importance of maintaining good relations with customers. TRX has done this consistently with me and that is why they get my vote every time.
Like any other exercise tool or implement, it’s all about how you use them. You get out of it what you put into it! For similar pieces of equipment (e.g. treadmills made by different manufacturers, suspension trainers, stability balls etc.) the exercise “concepts” are the same.