The one who invests his time demoing them for you. Cheers,
Audio Research doesn't like their dealers selling out of territory, so you will have to go to individual dealers, explain why you want, and see what they say. When looking for a discount it always helps to have a relationship with a dealer. First timers usually don't get a "best price". If you want Audio Research at a discount look for used here.
The best time to buy ARC is right when a "new/improved" model is replacing the now hardly-worth-listening-to obsolete model, which is every other year or so. Right now you should be able to pick up an LS17 or 27 or whatever (I’ve lost track) for a couple thousand off list. Check the outside of the sealed carton for the stamp "Factory Reconditioned", a method ARC has used to get rid of pieces returned for repair but never paid for.
I've owned a lot of ARC gear through the years and all of it sounded really good. The only fault I could find was in demoing the next generation and making the comparison. I enjoyed my first ARC system as much as any of the later versions which cost much more. I think it's always a good idea to step back and try to gain some perspective on this 'rather addictive' hobby.