Well, let's see. Right now the price for the M&P9 range kit is: $630 comes with 3 mags. Includes Blade-Tech® Kydex® Holster, Blade-Tech® Double Magazine Pouch. Canik TP9SA kit is: $569 comes with 2 mags and a holster that has been reported to be pretty marginal.
The M&P9 comes with 3 sizes of backstraps. The Canik TP9SA doesn't have this option (one size fits all). The M&P comes with a Stainless steel slide that is either coated with Melonite or PVC (Police versions) coatings. The Canik has a regular steel slide with a Cerakote finish.
The M&P9 is made from better materials (stainless slide with melonite coating) and better more adjustable overall design (multiple back straps). The range kit comes with 3 mags, a good holster and mag holder. There are only two real negatives I have over it. 1) The trigger is about a pound heavier than most striker fired pistols it's competing against (plus it's not that smooth at first) . Like the Glock, you press the trigger prior to take down. 2) Accuracy is mediocre. Which could also be a product of the trigger. It's not a target pistol but still I would have hoped for better from an otherwise pretty good all around pistol.
The Canik TP9SA is a good modified copy of the Walther P99. It comes with 2 mags and a garbage holster. The TP9SA has a very nice trigger. Not as good as my PPQ but pretty close. Considering this pistol is a modified copy of the P99 which was the predessesor of the PPQ, this shouldn't be a surprise. It's well made with good fit. The finish is Cerakote. Not my favourite but it's ok. Accuracy was ok. Frankly I expected better. My PPQ shoots exceptionally well. The Canik shot better than the M&P9 but not by much at all. Again, I was unpleasantly surprised by this. I really expected more. I tried multiple 9mm rounds from various companies and in various weights for both the M&P9 and the TP9SA. The main negatives I have over the Canik are 1) The decocker. Good for disasembly but it can deactivate your trigger. This was a throw back from the double action where it makes sense and doesn't leave your pistol requiring the slide to be racked to work again. It takes a fair bit to press this and it's unlikely to have an issue, but still. It's something that can't be ignored. 2) Accuracy was ok but nothing great.
Value: The Canik TP9SA is supposed to be a well made "value" option of a high end firearm. Turkey can make some pretty good firearms and some of their factories have the various ISO 9000 ratings. In the USA this pistol is $355. In Canada it's $569. The M&P9 range kit in the USA is $538. In canada the M&P9 kit is $630. At this time, the clear value winner is the M&P9 range kit.
I would buy the M&P over the Canik anyday. In fact I did.
That being said I would spend the extra and get a PPQ or one of the other competitors that I mentioned to the PPQ.