I have a Glock 17 Gen3, this one was my first pistol ever actually. Got it for around $526.00, that would be a good price if you find one for that.

Good choice on a gun, there's no gun that has the amount of firepower capacity and reliability like a G17.

I would try and shoot one first before I bought it. I got a Gen 3 G17 and it is my nightstand pistol. It's a Glock at a great price.
I got mine for $425 and love it. I do like the XDM Springfield more however. Good luck on your next purchase.

I own several Gen4 Glocks in various calibers, and have fired several more, but unfortunately, I have not yet had a chance to shoot a Gen4 Glock 17. The new Gen4 Glocks in 9mm seem to have slightly heavier springs than the older Gen3s, so in some cases, owners must use full-powered ammo for best functioning results. All the Gen4 Glocks I own and have fired have been flawless with ALL ammo types, but a few folks have experienced problems with the cheapest ammo types and the some Gen4 9mms.

I usually tell folks that unless they have a specific need for one or more of the Gen4 features (lefty mag release, smaller grip), they might be better off sticking to the Gen3 Glocks for a 9mm with a proven track record.

Thanks for the advice, I am a lefty too. So maybe the gen3 would be better for me?

Well, you are one of the folks who would benefit from the reversible magazine release button which is only available on the Gen4 guns, but most lefty shooters I know have been shooting right-handed handguns for so long, they are used to using the right-handed controls. If you fall into this category, then I'd recommend the Gen3 Glocks. If you want the option of a reversible mag catch, and the smallest possible grip size (the Gen4 frame with no additional backstrap installed is slightly smaller than a Gen3), then a Gen4 would be a better choice.

Mag options/availability is another thing to keep in mind: to set up and use the mag release button for left-hand use, you have to have the newest generation of magazines that have the extra notch on the left side. Here in the US, all new full-size Gen4 Glocks will come with 3 magazines that are suitable for left- or right-handed use, but if you buy extra mags, you'll need to make sure they are compatible with the Gen4 left-hand release. Older mags can be used if a Gen4 is set-up as a right-handed release, but pre-Gen4 mags won't lock-in and function if the mag button has been swapped for lefty use. New Gen3 full-size guns sold in the US will only have two mags in the box, and extra mags are hard to find right now, so that could be a factor in your choice.

Finally, the grip texture on the Gen4 Glocks is very aggressive; some folks like it (gun doesn't move in your hand when firing, even if you're sweaty or cold), other folks don't (can be abrasive on hands, clothing, vehicle seats, and muffin-tops (I'm NOT in any way saying you have one, as I've never seen/met you -- but I have a bit of a problem in that area, and with a Gen4, it was a factor in my IWB holster choice)). In 9mm calibers, the gun doesn't jump around all that much during recoil, but in .40/.357, or during long shooting sessions with the 9mm, it can wear a sore spot on your hand depending on how you grip the weapon.

To see a comparison of the grip frame texture, you can click on the Stickied thread near the top of the Glock forum showing the different generation frame types. Here is a close-up of the Gen4 grip texture:

I got a G17 Gen 4 a couple months ago for IDPA. Great gun shoots accurately also.

The only problems with the new Gen 4,s is that new double spring . Change it and go back to old style single spring and all is well.

I'm not a Glock expert by any means, but I do listen to what people say about them. I keep hearing that Gen 3 is the most popular, and when they go shopping for one, it's the Gen 3 they look for, regardless of model.