I once owned a glock 22 way back when they first came out and got rifd of it because I just don't shoot glocks well.
Yesterday, I borrowed a SIG 229R DAK in .40 and DAMN !!  I shot it well and the ergonomics were excellent.  I shoot SIGs great anyway though.
I've always been a .45 and 9mm guy but this SIG has me thinking a bit different.  
Soooooo, tell me why I need a .40 !!
Or why I don't.

Whatever caliber you shoot better. I'd stick with 9mm or .45 as I don't really see the need for .40 but YMMV.

Who cares if you need it.  The real question is do you want it?  If you do, get it.  Remember variety is good.

I like the .40 because you get nearly the ammo capacity of a 9mm with a round that is arguably as good as .45 in putting BGs down.  

.40 is supposed to be the comprimise between the 9mm and the .45.

It's supposed to have more speed than the 9mm.
It's also supposed to have more stopping power than a 9mm.  


Get what works for you.

My friend brought home a new sig226 rail .40 the other day from h&h in OKC and we took it to the range friday and damn......nice gun indeed. I love the egronomics of the sig. It fit my hand like a glove

Quoted: I have a G27 and love it.  I would like to get a full size 40 as well.  The 9mm and the .45 are great because surplus ammo is readily available.  But as the .40 has become quite popular, .40 can be had a price equal to 9mm and .45.  Personaly I have all three calibers, the .45 is my favorite, but I'm just a collector/shooter so the caliber isn't all that big a deal to me, as long as it's commercially produced.   I say go for it, whats it gonna hurt to have another pistol, and another caliber?  Nothing as far as I'm concerned, it's all about Diversity.

AND

Quoted: .40 is supposed to be the comprimise between the 9mm and the .45. It's supposed to have more speed than the 9mm. It's also supposed to have more stopping power than a 9mm. Get what works for you.

Obviously we have a little bit of misinformation in this thread. First I bring you offical Wal-Mart pricing on pistol ammunition :
1. 9mm 115gr Value Pack (100 Rounds): $11.97
2. .40 S&W 165gr Value Pack (100 Rounds): $15.99
3. .45 ACP 230gr Value Pack (100 Rounds): $19.99

Prices seem like 9mm is cheapest, .40 is more, and 45 is more.

Next, speed. The 9mm is going roughly 1100 fps, while the .40 S&W is pushing along at a respectable ~1175. .40 S&W is faster.

The .40 S&W is an excellent round and I think it would be great for nearly any use. It has high magazine capacity (13 in a USP), and packs more foot pounds of energy than the 9mm and some .45 ACP loadings. No round in a small arm is going to knock someone off of their feet. It matters where you can place your round to inflict an injury that wil stop the threat from being a threat.

Lesson
It is to your advantage to take the biggest round that you can still handle. A hit with something small is better than a miss with something big. A hit with something bigger is better than a hit with something small .

This is just going to turn into another caliber war so my advice is that since you like the gun go buy it.

There's some balistic overlap between some of the 9mm and 40 cal rounds (the same is true for 40 and 45).  I believe 45 acp is still one of the best self defense rounds made, but most pistols that accomodate 45 with double stack mags are uncomfortable for me, especially when carrying concealed (advantage 40).

The 40 throws larger, heavier rounds down range at the same velocity as the 9mm....which should give it more stopping power in theory.  The 40 is also comfortable for my hands, when using double stack mags (advantage 40).

These are also reasons that many law enforcement agencies have started using 40 over 9mm and 45 acp.  I would suggest you shoot all three to see which is most comfortable for you.  I obviously prefer the 40, but it has a pretty sharp recoil when compared to the 9mm.  

www.neiassociates.org/caliber.htm

Here's a link with some valuable information about caliber selection for self defense, using available shelf ammo.


ETA: I use 180 grain FMJ for plinking at the range......$10.99 a box.  

I can relate, I’m a bit of a 9 fan my self where as my brother likes .40. I feel better with a little more capacity, he feels better with a little more power. I can see both sides being valid, but nothing to start an ammo war over! 9mm .40 .357 SIG .45 what ever is good for you, I’ve got nothing against any of them. But here is my favored ammo for the .40, Premium® Personal Defense: Increased muzzle velocity and energy at a reduced recoil.
I recommend this ammo for compact or sub-compact pistols. It’s a fun load to shoot in any caliber or platform, JMO. Now I’m sure you can handle big boy rounds, but with the stress that might come with fighting for your life, who knows? You got to practice like a special forces solder to find that out.


What ever is clever man

OK, let's be honest.  You don't really NEED a .40 for any real reason.  The question is can you afford it without any problems?  Do you want it?  If those answers are both yes then I say go ahead and get it.  

I am considering picking up a 299 SAS in .40 if I can find one here in a couple of months.  Please let us know how you like the 229 if you do get it.  

Do yourself a favor,try the 10mil(rent one)then see if you think the 40S&W is the snittzel!!!

Can you get the 40 in 200 grain?

Bob