I agree; Bucas has a great cut around the neck which seems to be equally good for both my rather narrow girl and my friends chunky boy and I'd even say it's a better fit for him. Not the "economy" Freedom range though (Freedom cut is really narrow) - go for Smartex or Power (not sure about Irish and Select).
They also do a big neck cut for horses with really big front like friesians, PRE, stallions etc. but for this black boy standard neck is plenty enough.
I've had a lot of trouble finding a rug to fit my quarter horse. He's the "bulldog" type - built like a brick s***house. I decided on the Weatherbeeta Genero Wide. I have to say that I'm really pleased with the fit. If I was to be extremely picky - I would have liked it just a weeny bit bigger in the shoulders, but really the fit is very good. Plenty of room in the back end for his big backside too. The quality is good, and it was not expensive. Would have liked a bigger tailflap though.
Maxima equestrian fit nicely with loads of adjustment at the front. The quality isn't up there with bucas or rambo, but for the price I wouldn't expect it to be.
Usually I go for the weatherbeeta but even these weren't wide enough for my big shouldered cob but I have discovered rugs from the big horse shop. Plenty of room all round and huge tail flaps. They are true to size and excellent customer service. Highly rate. The only bucas I have ever tried was the fly rug and I found it narrow on the chest.