baldheadracing wrote:A PID is more-or-less irrelevant on a single boiler dipper machine like a Pro 800. A PID is less expensive and, for the same cost, more reliable than a pressurestat. The only advantage of a PID in a machine like the Pro 800 is that changing settings is easier - however, the effect of changing settings is the same, pressurestat or PID.(A PID does have an insignificant deadband, but that is of little practical value in a copper service boiler the size of the one in a Pro 800.)

As for similar performance, I'm not sure if I understand you. They're very different machines. The groups are different, the springs are different, the boilers are different, the pressures are different, the temperatures are different, the brew water feed mechanisms are very, very, different, the pump usage is different, the pre-infusion mechanism is different, etc. Sure, you can get the same shot out of both machines, but that is on you and your technique, not the machine. Use them in their default configurations/techniques, and you'll get different shots.

I don't know if your research has uncovered this, but just in case, the underlying point is that, with the exception of the LM Leva X and the new Kees Slim Jim Idro, all - ALL - other current factory-made commercial-sized spring lever groups were designed for traditional Italian espresso (just like the E-61). That doesn't mean that they can't handle light roasts, but it does mean that you - not the machine - you - have to tailor the extraction to handle the roast. The Strega and the LR24 - and I presume the ACS - somewhat simplify that tailoring process in comparison to more conventional machines like the Pro 800 (IMO). Even so, when I have a nosebleed-light filter roast, my first choice of lever machine is the Elektra Micro Casa a Leva, which is a machine well-regarded for the clarity of the light roasted espresso that it produces. The (single luongo) espresso that it produces by default will blow away my commercial-group levers - unless I "work" those machines (and I'm lazy these days).

Regardless, have you considered a Robot, or Flair 58, or Espresso Forge? I would strongly recommend getting one of those first and figuring out lever espresso first before investing in a lever machine. You could end up preferring the espresso from your Mara X ... and, as always, spend your money on:
1. Coffee;
2. Grinders (yes, plural) to get the best out of the coffees; and
3. at a distant third, the machine.

Good luck!

BKH wrote:I have a regular stock Strega tank. While it is not the most tricked-out temp adjustable machine, I appreciate being able to do a flush to greatly adjust temperature.

To my taste a lighter roast coffee can be tasty with no flush or short flush (higher brew temp), while a dark roast or blend with robusta can benefit from a full HX flush like on an e61 where I no longer see sputtering water coming out (lower temp so that the roastiness/burnt is less pronounced). That allows me to single dose very different coffees back to back to enjoy the variety without adjusting any PID or pStats