If I was looking for a compact or full size (4" or more) 9mm for under $400, action wasn't important but it had to be new, I'd look to a handful of options:
-I know you don't want Taurus. With the reputation, I understand. I've had great luck with their revolvers, the autos... my PT140 Millennium Pro was a great gun, until it wasn't anymore. That said, the steel framed autos have always been pretty good and you can probably get a PT92 for under $400. If I was going to be hard and fast to $400 and not a penny over, and it had to be new that would probably be my top choice. I'd also take a close look at the polymer guns since the prices are so attractive right now (for that $400, you can get a PT111, 24/7 or 809 and 100-200 rounds of ammo).
-The SIG P2022 that others have mentioned would be a terrific option if you can get it for under $400 (or more likely, if you are willing to go 10-20% over that budget). Around here, they seem to run more like $500-550, and remember to add back shipping and FFL transfer fees to that $400 gun online (around here transfer fees seem to run about $75). If I did see one for $400 locally, it would probably be my first choice.
-The CZ P07 is pretty much the same story as the P2022. Around here, they tend to run around $500-550, online I've seen them for less, but not after FFL transfer fees are considered. A lot of the people on this thread must have very nice local prices, if yours are similarly low this and the P2022 would be my top choices.
So, discounting those you say you don't want (Taurus) and those that seem to be pushing your stated criteria (they'll almost certainly be over $400), my more realistic suggestions:
-Kahr CW9 or CT9. The CW or CT series is their budget line and you can probably find one for under $400. I know Kahr seems to be a love it or hate it gun (many don't like the 200 round break-in), but those I have had first hand experience with (friends have had a few) have been terrific guns. I'm not crazy about the 7 round (CW 9) or 8 round (CT9) single stack mag though (I'd prefer a double stack with 10 rounds or more). They are a little under 4" but they are as close to a traditional compact (smaller service size) pistol as you will find from Kahr.
-Bersa. I'd go with some variation of the Bersa T9 Thunder. I had a Bersa Thunder .380 for some time about a decade ago and it was a good gun. I've read very few complaints from Bersa owners. It may be the best budget option out there, though most of the Bersas will be a tad under 4".
-SIG P250. You might be able to find one right at $400. I love my .45ACP P250 Compact. Reliable, accurate, great size. The modular design makes them very versatile as you can buy conversion kits for other calibers or sizes, and you can also vary the size of the grip module within the different frame sizes for different sized hands. Out of these three options it would be my first choice, but you'll be right on your $400 ceiling while the others may be a few bucks under budget.