The M31 is a slightly better machine. But it looks kind of old. It is possible to see how many shots it has produced so you can get a general impression of the use it has had.
I honestly think the M29 is a better buy. They are a little more forgiving then the M31.
But the real questions you should ask before buying anything used is how has it been maintained? If they have been serviced by a professional company can you contact them for service records? Have they used a water filtration with softening system? How old is the equipment? What is your idea of low volume?
My back up espresso machine is a Cimbali M29 Select. It's a nice machine but its small 5 liter boiler exclude itself from heavy milk steaming. On our regular 3 group machine, we sometimes use both steam wands together and never miss a beat. On the M29 you definitely will notice a drop in steam power. I would say if your peak volume is no more than 15 - 20 16oz milk drinks an hour, M29 is a solid machine, more than that you should look for a 10+ liter machine.
The look of the 31 fits in with my place (tin ceilings mahogany panels leaded glass etc.) so for me thats a plus. Are they comparable machines,do the prices seem fare,I would guess the machines have to be hooked up so I can test them (common sense), is one more difficult to maintain than the other(parts labor etc.)will the 31 do much more volume than the 29,in your opinion do I not even want either or should I be looking for a different type all-together, how do I check how many shots the 31 has produced. As far as volume, there's no way for me to project that, 3 years ago I changed my Boston(just outside downtown) antique shop into a coffee shop.The neighborhood has been rapidly changing to a higher priced, (condos professionals)place to live. My regulars love my hot and iced coffee, but the new cliental want espresso etc. My place and the neighborhood is ripe for it. So I come to you folks and humbly ask for guidance, direction and advice. I do realize the final decision lay in my lap, but it is wise to tap into other peoples experience, especially when the subject is so specialized. What should I look for when I go look at these machines? I never made a shot of espresso in my life and I sincerely appreciate your patients and help.Joe
The Dosatron is a bigger machine. 10 liter boiler, 4500 watt element. The pictures show only 2 steam arms. One is mechanical and the other is push button. You could technically convert the left side back to a steam arm. It also has a different fill system (can be a little finicky) and a display for easy programming and counter info.
If you can't tell I'm not a big fan of the fill system. Other then that it is a better machine. The Dome on the top is for show and is not included with the purchase of a new machine. It just sits up there taking cup space.
Either way it could be a costly venue if either machine needs repair. Cimbali states every 5 years a major overhaul should be preformed. Typical overhaul runs between $1500 and $2000.
With few exceptions most used espresso machines needs some kind of over haul because most shops took poor care of their machines. If you buy a used machine, have a espresso mechanic do a top to bottom check, and if you are luck, your repair bill will be small. My mechanic for ease of repair reason loves Cimbali. In the Boston area there is a service guy in Medford. He probably can tell you about those Cimbali as he probably sold those in the first place. http://www.espressoplus.com/
The best coffee shops in term of coffee quality in Boston area is Simon's on 1736 Massachusetts Ave, Cambridge. You might ask them to give you a hand on espresso. They don't do Starbucks type of 20oz drinks, they are into straight espresso and 5oz cappuccino.
You folks are the best, I got the 29 for a great price. I was actually able to track down the service man who installed it new and serviced it(espresso plus) thanks to your posts he remembered it and gave me the thumbs up. Now I need to get a good grinder (any thoughts).Oh and the hard part, I need I need to learn how to make and market specialty coffee drinks ha ha. Joseph