Indeed, the M-DAC has been well-reviewed and most people seem to regard it highly. What I'm saying is that if Westlake sees so much 'room for improvement' with his own board component upgrades, software updates and a full blown PSU unit to replace the power brick type thing, and one is tempted to get them, considering the wait, the cost (and invalidated Audiolab warranty in the case of the first two), it bumps the price up to the level of several other DACs that wouldn't have invalid warranties and have better power supplies as standard.
If someone is looking for a combined DAC/headphone amp, the M-DAC looks to be a great choice at it's price point and bar the D18 I think it's the cheapest way to get a Sabre-based DAC, at least here in the UK. What I'm saying is that for £599 + another £400 or whatever it was for all the upgrades... that you're stepping into territory occupied by several other well-regarded newish DACs that don't have these potential hazards. If my budget only covers the M-DAC as stock then that's all I'd be thinking about, but if I had £1000 to spend, it wouldn't.