I think 'best' is going to mean different things to different people,
In mine I've used silent coat to add weight to the panels and had enough left over to cover the entire wheel arches, it's thin enough to allow me to fit moulded plastic covers (from Banwry) over the top for a clean uncluttered look.
In terms of noise reduction it's much quieter than before but do bear in mind I did all the rear panels, tailgate and sliding door at the same time so i can't say that the wheel arches on there own are better!
I put a layer of flash banding on the arches for damping, then coated the arches with some Mass Loaded Vinyl (MLV) - also known as Mineral Loaded Barrier - after that I put a set of wheel arched liners on from Banwy to tidy it all up.... one thing though is dont forget to line the arches inside the panels - else the sound just bleeds through!
Before splashing on some Dynamat have a chat with Paul @ Classic Acoustics in Telford
i removed the plastic wheel arch liners and spray 3M Body Schutz, not too much, then put the liners back on and another good layer of Body Schutz. consider the underbody also. bit of work but it helps.