The weatherby element is a fantastic gun for the money, but it is 6.7 pounds. To me, and maybe it is just the balance of it, but it feels heavy to me. But it is a great gun for what it costs.
The Retay Gordion Compact with the 24" barrel is pretty nice gun. I like their barrels especially. There is no plastic on it in the obvious places like trigger guard, etc. which is nice. It is very balanced when put to the shoulder. We just got one cerakoted and are fixing to pattern it in the next week or two.
The Mossberg SA is a flip of the coin. It seems that about 60 percent who get one say it is the best gun by far that they have ever owned. The other remaining 35-40 percent say something far less positive. It may be the best looking gun out there to the eye, and I thought seriously about getting one, but I cannot get past some of the stories from that 35-40 percent who say bad things. To be fair, alot of it may just be that folks are shooting too heavy of a load in them. I think that gun is only rated for a 1 3/8 ounce load.
While I do not own a Beretta A300, I personally have not heard any negative on them and assume that it is a solid gun and would serve one well.
If you are not totally hung up on a Semi-auto, why not just buy an earlier made 870 youth compact off of gunbroker and put a meadow creek mount on the rib and add a red dot? You can change the stock if the LOP bothers you and come in under 1000.00 easily and likely never have to worry about the gun not going bang in the woods - like literally ever. And I have yet to see a 870 that would not shoot lights out with the right choke screwed in the end of it.