• Price (paid $880 for this heat exchange unit)
  
• Reliability (no problems in six + months)
  
• Better shots than lower end machines (admittedly subjective...but I upgraded after using a Silvia for a couple of years).  Crema color lasts longer than lower end machines.  (by between 5 and 10 seconds)
  
• Very fast steaming/frothing
  
• Large Water Tank and drip tray
  
• Nice preinfusion options

• Heat exchange heats water too hot when sitting idle (requires temperature surfing like all non-PID temperature controlled machines)
  
• Heats milk *very* quickly, which is a plus...but...it takes a lot of practice to get microfoam.  After six months I still can‘t get the same quality froth I could easily do from the Silvia.  But...I‘m getting closer. *The bolts on the weight sensitive metal floor below the water tank begin rusting within a few months!  Make sure your Isomac Tea uses brass bolts or some other material that won't rust.
  *The drip tray will leak (if it gets full enough) from where its handle attaches unless the bolts are screwed on very tightly.  A simple solution might be plumbers tape or some sort of rubber washer.  I have enough handyman chores like that around the house so I haven't bothered to fix this.  I just dump the water out before it gets that high.

Would I buy this machine again for $880?  Yes!  (And mainly because I‘ll never be able to afford a Reneka Techno!)  This is a wonderful machine that has left my Rancilio Silvia in the dust (even with temperature surfing.)  I "temperature surfed" (do a search on the subject at Google‘s alt.coffee if you don‘t know what that means) with the Silvia and still surf with the Tea.  But I *think*, based on a perceived increase in  sweetness and smoothness in the shots, that I get better thermal stability with the Tea.  (I believe the preinfusion also helps.)  The color in the shot lasts longer than it did on the Silvia (though it starts out a lighter red because of the preinfusion).  Like so many others, the most challenging thing for me in upgrading to this level of machine has been "relearning" to froth milk.  The milk heats up so quickly you really have very little time to work with.  I‘m certainly better than I was six months ago, but I‘m not where I was with the Silvia.

I really like the preinfusion offered with this machine.  The way the mechanism works gives you great control over preinfusion.  It is possible, by lifting the lever up only part way to preinfuse the coffee without turning on the pump.  Water from the E61 group gently soaks the coffee puck.  This is the method Max Orsini prefers.  I prefer to let the machine preinfuse do all of the preinfusion by simply lifting the lever all the way.  Nevertheless, it's fun to have the option and be able to experiment.  In addition, the lever allows me to turn the pump off at the end of the shot without pushing the lever all the way back down.  Often when the coffee group/portafilter is depressurized after turning off the pump, a lighter more acidic crema gets pushed out into the cup (yes I know I'm being a bit obssesive here...but if you've read this far...you must share my obssession!)  I used to pull my cup out mid stream to avoid this.  Now with the Isomac I can lower the lever part way to turn the pump off, remove my cup, and push the lever down the rest of the way.  It's a pretty small thing, but it's fun to have that kind of control.

The machine has a 1.8 liter boiler and uses a heat exchanger heating the water for coffee.  I can't tell you how long it takes to heat up as I leave it on 24 x 7.  I do wish you could adjust the boiler pressure (and consequently, the water temp) without taking the cover off.  But I consider that a minor inconvenience.

The service from Max Orsini has been great.  I called him several times for advice on frothing.  He also sent me a four hole steam tip for the machine for free.  In the end, however, I settled on the original two hole tip that came with the machine.  I very much enjoyed doing business with Max and hope that someday I can visit his shop in Oregon.  If I get the opportunity, I will probably bring my machine down and have the bolts that secure the weighted metal floor below the water tank replaced.  After only a few months they began to rust!

My wife and I both use this machine daily.  We love it!  The shots have been amazing.  The Espresso Vivace Vita milk based drinks at home now taste like they do at Vivace, though I‘d never be up for a side by side taste test!  The Caffe D'Arte straight shots taste better at home than they do in their shop.

We also use the hot water dispenser for tea.  Some have posted concerns about tapping into the boiler water for tea (noting that "heat exchanged" water is fresher).  The hot water has never tasted stale and it has never been a problem.

Tip #1:  This applies to all E61 grouphead machines.  If you leave the machine on all the time and don‘t want to throw away the first shot every time...don‘t leave the portafilter in the group head.  It will get too hot and take too much water to cool it down.  Leave the portfilter on the warming plate above the machine.  Run some water through the group head to cool the group head down, then put the portafilter in and run some water through to heat the portfilter up.  Follow this tip and you won‘t have to throw away the first shot!

Tip #2:  Turn down the heat!  Most heat exchanger machines come with a preset boiler pressure that is too high and will burn the coffee.  I thought turning down the boiler would make it harder to froth (lower steam pressure.)  For me it's actually made it easier as I have a little more time to develop the froth.  FWIW, My boiler is currently set to just slightly above 1 bar.  Experiment with this to find what works for you.

I had a great buying experience with Max Orsini of Caffe Orsini.