I have the G19 version in the Gen 1 and Gen 2 models. I love them both as I am a big fan of pistol caliber carbines. The Gen 1 can be a little finicky if it is not kept clean.
My only thought on the G17 version is that you are limiting what Glock mags will fit it. A G19 version will take G19 & G17 mags. A G17 version will not take G19 mags.
I have a gen 2. 500+ flawless rounds through it- with magpul mags and a Glock brand giggle stick. I am very happy with it! I haven't gotten too crazy with it, simple laser and light and some ladder rail covers. The irons are really nice on the gen 2 so i haven't added an optic.
I've owned two. Sold the black one and kept the olive drab one. It is softer shooting and quieter than the Beretta CX4 Storm that I owned. Like that it folds up and fits in a backpack. Bought it for overnight trips as added security over a CCW handgun. It has been a reliable and accurate little rifle. Have picked up three extra Korean 33 rnd mags and two extra Glock 17 mags. Feeds reliably from them and MagPul G17 mags.
I think Bradis has the best deals on them brand new. The second one I picked up at McDonalds Gun Shop near Marion/Gas City. He had a couple of new ones and a couple of used ones in stock, a few weeks ago. His prices were also very good.
Mine is 17...there's really no difference between the 17 and 19 config...sure you can say the 19 will hold the 15 round glock 19 mags....but I really don't use anything other than 33 round glock magazines in mine..