I like to stay as unbiased as possible when recommending brands. I will list the most quality brands as rated in the industry:

1.) G3 Boats - as the name implies it is the 3rd generation of the Lowe family that originally started Lowe Boats. Upon the selling of the Lowes line to the Brunswick Corp the grandson Brent Lowe started G3 Boats. Noted for its quality production and located in Lebanon, MO. It was purchased by Yamaha in 1997 and the brand has continued as one of the premier Brands of the aluminum boat industry.
They build many "Jon" models and one of the only companies to offer like models in both riveted and welded models. Their welded models sport the heaviest gauge of most of the common "Jon" manufacturers with a .100 gauge thickness. They also have what is arguably the best warranty in the aluminum business.

2.) War Eagle Boats - Built in Monticello, Arkansas by the Ward Family. They are still a family run independent manufacturer that build a great product. They were the original manufacturer of the DuraCraft line back in the 50's-80's. Great quality but they dont build many models of true "Jon Boats".They only have one model in the 14-15' range. They use .080 gauge aluminum.

3.) Lowe Boats - Owned by Brunswick Corp who also owns Mercury Outboards. Quality product that offer many Jon Boat models. Caution must be noted as their 14' models are actually 13' 8" and their 16' models are actually 15' 8". Their 14 and 16 ft models sport a 48" bottom width and a 70" beam width. They also use .080 gauge aluminum in their construction.

4.) Crestliner Boats - Also owned by the Brunswick Corp. They are a good product and offer a good value for the dollar. They use the lightest gauge of the above other comparisons...which is .072 gauge. Resale is usually not as high as with G3 or Lowe.

5.) Sea Arks Boats - Older manufacturer with a good reputation of building quality products. Their web site leaves a lot to be desired as they dont give any real specs on their models. There is some question as to their current production on loose Jon type of boats and if they are still offering Jon Models.

Best thing to do is go to the web sites of the above and browse through their Jon offerings. Some offer flat straight bow fronts and some offer the Mod V bow front design on their Jons. Personally I prefer the Mod V.

Hope this gives you something to go on.