Hmmmm, lets see.... should I buy more of and different types of guns. AFFIRMATIVE!!! If you have got the budget then go for it.
As for the barrel length in an AR. If you are only going to have one upper for awhile - I would go for the 16 inch. A lot easier to handle and good for up close and out to a considerable distance. If you are looking mainly for varmiting and target shooting, then a longer 20 or 24 inch would be the choice. For all round use, however, the 16 inch is hard to beat. Forget the muzzle brake. You lose up to 1.5 inches of barrel and create a lot of noise without any real benefit. If you are worried about recoil then you need to stay with the .22LR and not the .22 and a 3rd. However, if you like the look you might want to look at the LEGP. It has a pressed fit bird cage that looks real good and you don't lose any barrel length nor annoy those shooting next to you.