What Turntable to buy under $600 ?

>>If a table is suitable for broadcast and DJ duties would it not be already some way towards the goal of good sound reproduction?<<

Faulty logic. These tables were originally designed for bull work, heavy duty use, and durability not superior sonics. Hope that helps you understand.

I respect your flawed opinion. We are not using Wheatons, Schroeders, and Grahams because of hype rather their ability to track more accurately than a Rega with an inherently poor bearing design. Again I repeat, no real reference analog system uses Rega tonearms. This is not a vanity issue simply one of performance. Read the threads on Audiogon my friend and see what tonearms are used with the cartridges I mentioned. Time to smell the coffee and live in the 21st century. Indisputable to an informed audiophile. Come join us.
I deliberately did not mention Koetsu, because like the dinosaur, they have outlived their usefulness and purpose to live forever in posterity with the Desoto, Edsel, Lafayette, Heathkit, and Scotts of the automotive and audio world. They have been replaced by Zyx and Shelter. Enough is enough. This is much too easy.

Rega tonearms are far far far from being "world class". They will not track ANY of the finer Zyx, Shelter, or Dynavector cartridges accurately. That is indisputable.

None of the pick ups you listed are among the truly high performance cartridges I was alluding to. Those include Zyz Airy, Zyx UNIverse, Benz Micro Ruby, Shelter 90X, Dynavector XX and XV-1, vdH Colibri and Grasshopper, etc. I'm sure the 300 will track the cartridges you list but I maintain, quite accurately, that it will not extract all of the information that a better arm will.
The 250 and 300 are nothing more than entry level to mid-level performing arms. To speak of them in the same breath as world class tonearms such as Wheaton, Schroeder, Graham, etc. is not only disingenuous but bordering on heresy. Nobody but nobody with a high end reference level analog system uses the 250 or 300 simply because they are physically unable to handle elite cartridges. Sorry to hurt your feelings but facts are facts. Good luck.
S

>>the choice of cartridge is by far the more important factor.<<

Nope that's flat out incorrect. A good tonearm with an average cartridge will smoke an average tonearm with a good cartridge. Check it out.