The thing about the portable testers, like tCheck and MyDx is that they compare your results with what they have in their database and then what gets displayed back to you is "the closest match", which in my opinion is useless because the specs for the strain aren't static. Even two or more samples from the same plant can have drastically different results.
The major differences between the two testers are that MyDx costs like $800 and the little test inserts are like $2 (but I think you can do 2 tests per insert) and the $70 sensor needs to be replaced every 6 months.
The tCheck is like $280, plus another $200 for the concentrate tester, the test insert is reusable, I don't believe there is a replaceable sensor, but there is a hidden $30 a month subscription fee otherwise the tester will just give you a Compound By Volume (CBV) value, which is all the cannabinoids combined and is totally useless, so they know you will pay the $30 a month so you can see how much THC and CBD you have.
I believe the tCheck 1 used to have you mix either the flowers or concentrate into some solvent and then put it in the sample tray, but now in the tCheck 2 model this is a $200 add-on.
One tester that has mostly been overlooked, is the SCiO, which is $300 and will test pretty much anything over about 1%.
The company claims the spectrometer wavelength isn't set up to test for cannabinoids, but I have read about how some folks have used it, though there isn't much available.
You see SCiO charges a small fortune for their development license ($800), which is totally stupid because the entire platform of their tester relies on third party apps and so SCiO is penalizing those who want to showcase the potential of the product.
It's bad business logic, because no one is going to spend $300 to buy the damn thing if all they can do with it is test the brix value of tomatoes or do simple manual programs that can tell the difference between obviously different objects.
Either that or it is some dick move to keep the product as some "elite commodity", which is great way to go out of business.
There are a few open source spectrometer projects, but I haven't been able to take the time to find one that is decent.
One day I would like to build one of these, if anything just to play around with it.
The tCheck is better then some of the other testers I have seen which are these overblown briefcase sized versions of the pocket spectrometers and have price tags that are in the (tens of) thousands and even some of those give you a "closest match..."
Anyway, I am sorry to go off on some tangent about the testers, but if there could be a meter that combined the best of the tCheck with the best of the MyDx, then that would be worth $800 or so...
In closing, here's a tester that will set you back almost $24,000 and requires about $100 a month in maintenance costs.
https://alliedscientificpro.com/shop/product/cannabis-thc-cbd-smart-analyzer-luminarytm-beacon-21342
This one at least gives you an actual measurement and not "the closest match."