Notwithstanding anything that anyone has already written above.
You have brought up a good couple of questions that I believe have very simple answers.
a) re the subject of topic. Ive never used a pid silvia but I consider myself to be well versed with a standard silvia and I import them direct. As far as I am concerned, silvia is the best domestic on the market under a thousand dollars BUT/...
when you compare it to a good quality semi commercial machine (whether it be a regular commercial heat exchanger type or a dual boiler type) I am afraid it doesnt cut it and the semi commercials will always (subject to operator expertise) brew a better espresso for whatever reason including that the semi commercials are more forgiving of operator technique.
I dont think there can be any doubt about it although some may wish to argue.
b) There is no need to be confused about the differences between semi commercial heat exchanger machines and semi commercial dual boiler machines.......
.....too much time is spent in forums like this picking them apart by way of their technical specs and the pros and cons of what some people think they can and cant do when the fact of the matter is, if you choose a good quality machine of either type, you end up with a great espresso machine.....if you have good technique and understand your machine it will reward you, and if you dont.........!
Essentially, they are two different internal engineering philosophies / designs that are a means to virtually the same end at that is, to make an espresso.....
..........and thats it.
If you choose well, in either type ( HX or dual), you end up with a great esp machine. If you choose badly, you end up with a crappy machine....but that is not to do with whether you have chosen a HX or a dual boiler type, it has to do with whether the manufacturers model you chose is a good coffee machine in toto or not.
My advice therefore is, if you are looking for something more than a silvia choose your price bracket, and then look at a range of machines in that price bracket irrespective of whether they are HX or dual boiler. Dont forget that a very important thing to ask about is ***reliability***.
And in the end, you will have to place your trust in the supplier of your choice.
hope this is helpful.
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