I've had both arms. The SME one is built like a tank and to SME's standards compared to the Hadcock, one reviewer said they actually preferred The M2's presentation to the revered IV and sounding slightly lusher. Its built on a very old school design of theirs called the 3009 but with some input from the Musical Fidelity supremo who saw the strengths of the model. many of the 3009 series from the 60's and 70's you still see on ebay, which is a testament to their longevity. Its called the M2 because it matched the limited edition MF turntable I had called the M1.
The Hadcock is a pain to set up, but does reward you with a lush classic vinyl sound. George Hadcock spent his entire life tweeking the design and theres probably about 8 different ones out there. The 242's extra length minimises tracking errors, and sounded awesome on my LP12 (I know its an odd combo). The wiring socket that plugs into the tonearm base from the wand is its achilles heel as the tags can come loose and its out with the multimeter!. Its actually designed so you can unplug it and swap tonearm tubes around with other cartridges set up, but how often do you need that is what you have to ask yourself! Last time mine went pear shaped Charles Hadcock (the son) still repairs these. It only cost £30 to get the wire resoldered. He's an interesting chap who makes massive sculptures in the same ilk but his own unique style as Anthony Gormley. There's something about the Hadcock, its just all that form and function I liked and the lovely polished finish. Its a gimble bearing which means it balances its fulcrum on a stainless steel spike, (I'm told from the horses mouth not to bother damping these with silicon fluid in the bearing). The M2 uses a knife edge bearing (an inverted wedge) rather than ball bearings. A company called Audio Origami can further enhance the M2 if its anything like the 3009's with rewires and new bearings, if you get money in the future and like the arm. Email them to make sure, Johnny is a very nice chap. The Hadcock has a captive tonearm lead, so its important to get the one you want when you buy, although George knew his stuff and wouldn't use a cable he felt compromised the sound although there are the silver and the cryo versions which elevates the performance further, the M2 has RCA sockets so you can use any interconnect that takes your fancy.
I have a weakness for the Hadcock, despite all the trials its put me through, but equally would have an M2 again. They are both spectacular arms IMHO, I'd say the Hadcock just pips it and its a bit different and actually a very fine sound for the price point.
