Wait til you start talking to water scientists with access to £100,000 lab equipment who still can't get reliable nitrate readings. All test kits are going to be hit and miss. Trust what your fish and plants are telling you over any of them. The only thing I regularly measure is conductivity, because it's the only thing you can reliably measure. It isn't terribly useful but it will give you a rough idea if there's a build up of 'stuff' which means you should be doing more water changes. I occasionally check pH if I've just calibrated my probe to check it's roughly where I expect it to be, but otherwise basing your fish keeping regime on test kits isn't a great idea as they're just as likely to be feeding you misinformation as helping. Disclaimer: I'm refering to freshwater stuff here, I have no experience with marine.
Personally I'd avoid Trimar. They have a massively over-hyped reputation because they give away copies of PFK to anyone who'll vote for them in the annual reader awards. They're local to me so I have a pretty good idea about their ethics and quality of stock and I no longer buy any fish from them if I can possibly help it.
If you want good mail order fish then try Wildwoods, Pier, Rare, Kesgrave or Sweet Knowle.
Care to elaborate? Because I got good mail order fish, and they were from Trimar. ; )