I'm working on my 9mm striker fired pistol collection right now. So far I'm up to my old Glock Gen 2 19, S&W M&P9, H&K VP9, Steyr M9-A1 and Ruger SR9.
So far my favorite has been the VP9. She has the most ergonomic grip of anything out there to the point you can have the hands of the elephant man and between the backstraps and side panels, there is a combination that is going to fit you. Reliability has been top notch and she's a freakin' laser in my hands!
The Glock is, well, a Glock. Reliable, rugged, accurate enough and aftermarket parts are everywhere. However, the ergonomics are not it's strong point. It works for me in that over time, your grip will adapt to the gun but the Block will not change to fit your hand. Live with it.
The M&P9 is sort of like an updated Glock. Mine has been just as reliable and my particular example hasn't had the accuracy issues that have plagued other samples, particularly the earlier models. The trigger wasn't all that great but a swap out to the APEX kit cured that problem. What is a big improvement over the Glock is the interchangeable backstrap. While not as good as the VP9, it still offers options over the traditional Glock design.
The Steyr has been an interesting pistol. Glock fans will generally mention bore axis and compare it often to the XD with a much higher bore axis. Well, the Steyr is to the Glock as the Glock is to the XD! The bore axis for those that care is probably the lowest on the market. The grip like the Glock is not customizable but I'm not sure that it really needs to be. It's pretty dang comfy as it is. Now the grip angle, like the Glock must be an Austrian thing as it's more akin to a Luger than a 1911. Like the Glock, you have to learn how to grip it or you are going to find yourself shooting high every time. It's a muscle memory thing. The sights are a love it or hate it affair. I like them although like the grip, it takes some getting used to. Now what I don't like is that mine hasn't been 100% reliable from day 1 like my other pistols have been. I've had a few failures to eject/extract but those mainly went away after the first couple hundred rounds. For good measure, I did add a 1911 plunger spring to the extractor spring to provide a little extra tension to the extractor. Like I said, it seems to have broken in now and I haven't had any further issues but I need to fire more ammo through it before I would rely on it like the others.
The Ruger SR9 is a nice pistol for the money. It's been reliable and has the best trigger out of all my pistols in this class. It's accuracy has however, not been nearly as good as the others. Another issue is that the rear sight won't adjust low enough to avoid shooting high. I am thinking pulling the screw and filing off the bottom a little will cure this problem. The ergonomics of the grip are pretty good even with the limited adjustments of flat or arched backstrap being the only adjustment. If you like the 1911, you'll like the SR9. I don't mind the huge loaded chamber indicator but I don't like a magazine disconnect safety. The previous owner must have thought the same and had already removed this easy to pull out piece though.
The soon to be added:
First on the "to buy" list is a Walther PPQ M1. It is very similar to my beloved VP9 but has been said to have a better trigger. On the other hand, the ergonomics is limited more so than the VP9 in that backstrap is able to be changed but the side panels of the VP9 don't exist on the PPQ.
Next on the list is the Canik TP9SA. A low cost Turkish made variant of the Walther P99 and from a lot of reports, a good performer. What I don't care for is the decocking plate that when depressed will leave you with a dead trigger until the slide is cycled. Knowing how Turks carry their weapons, I can understand why they wanted this feature but IMHO, it's a detriment that leaves open the possibility of going wrong at the worst possible time. However, that problem can be cured with a couple pieces of a wire coat hanger blocking that plate from being depressed. The other issue is that parts are not really available and Century Arms, the importers, don't have the best of reputations as far as warranty work. Better than some, but not nearly as good as most.
Glad it's working out for you.