Placed side-by-side, some might be tempted to judge the Macap M4 as simply a flashier Mazzer Mini. It's true that there's a lot of "me too" similarity, but there are several genuine improvements on the time-tested king of the hill. Let's begin with the doser. The upper portion is composed of a thick, tinted plexiglass cylinder. Similar to the tinted hopper, it hides mess well, appealing to the neatnik in me. The doser handle has light spring action and the cleanest sweep of the doser grinders. Score another point for those who prize tidiness. The portafilter rest is made of a thick, sturdy wire frame that offers no ledge for grinds to collect.
Like the Cimbali Junior, the doser arm is enclosed in the bottom of the doser itself. This gives a flat surface to the bottom of the doser so you can hold up a shallow collection container directly against it. This comes in handy when you switch from dosing directly into the portafilter for espresso to grinding for presspot or drip coffee. If you try the same trick with the Mazzer Mini doser, you must hold the container away from the doser bottom while flicking the doser handle otherwise the travel arm collides with the container.
Changing the grind setting is easiest with the Macap, albeit without with the same level of granularity as the others. Pushing down the pin release on the left allows the collar to spin freely, so moving the setting from espresso territory to presspot and back is a snap. This quick-change ability appeals to coffee drinkers who enjoy different preparations, but it comes at some loss of the ability to fine-tune the shot timing exclusively by changing the grind.
The increments between each adjustment correlate to approximately six seconds of pour time for most espresso blends. Quibbling about two or three seconds seems a little extreme to me, but if you really want to tweak the grind within half the width of a gnat's eyelash, the Macap's and Cimbali Junior's worm drive adjustment will get you there. The Mazzer Mini, because of the stiffness of the collar's movement, limits easily repeatable adjustments to a millimeter or two, corresponding to an approximately equal number of seconds.
Macap was the first to introduce the "shorter" hopper so their grinder would fit under US cabinets. I suspect some buyers went for the Macap over the Mini simply for that reason; Mazzer followed suit a few months later by introducing their own vertically-challenged hopper (now the standard). The major difference between the two grinders remained the stepped versus stepless settings and I frequently wondered why Macap didn't introduce a stepless sooner.
The stepless M4 was introduced to the US market in March 2006. It is the same as the incremental model, except the plastic trim ring over the metal adjustment collar is replaced with a toothed one and then a worm-gear adjustment is bolted onto the top of the grinder along the backside. Two finger adjustment from either side will please both left and right-handed baristas. One turn of the stepless corresponds approximately to one increment of the stepped M4. I would estimate the number of turns from an espresso grind to French press is more than 30 turns, but a lot less than the Cimbali Junior's worm drive, which was too finely spaced to bother counting.
In any case, the Macap stepless allows easy minute adjustments of as little as two millimeters, which compensates for pour time differences of approximately two seconds.