Re the Hottop - I wouldn't worry about the smoke - if you have ventilation that's good enough IMO. Unless you're
really into dark roasts I suppose. I just use mine in the kitchen and open a window to blow out whatever smoke I get - but it's not a lot really. Certainly nothing compared to what I get if I take the smoke filter out. That smoke filter does an excellent job.
Re the Gaggia, the boiler sprang a leak and blew water all over the electrical circuits. Thankfully the circuits survived the experience and the repair actually didn't take all that long once the man started on it (about an hour).
However (and here I must apologise to those who've heard me tell this story several times already
) the TD is an unusual machine in that it not only is a heat-exchanger (HX) machine, it has supplemental electrical heating at the group head, controlled by a thermostat buried in the head. Someone once described the Porsche 911 to me as a triumph of engineering over design. I think this falls into the same category.
Anyway, the very earliest TDs (from 1995) had electrical heating in only one of the two groups (the one furthest from the boiler). For machines which get only light use, or for that matter where the barista is in the least concerned about temperature stability, this is not good enough. As an example we tested the water coming out of the groups. The RH group produced water near 90 dec C but LH group produced water at only around 73 deg c. The engineer who sold me the machine was going to install a later model group head for the LH group, but something bad happened to him and I never saw him again. It took me a long time to find a commercial engineer willing to actually fix the machine for me, but he's not a Gaggia specialist so he's having problems getting a replacement group head. The machine has stayed with him for several months now, firstly because he didn't fix it for quite a long time because he was busy doing other stuff, and then because he couldn't get the spare part. Last I heard (two weeks ago) he still hadn't managed to get it. I'm going to give him another week and then I'm going to get him to bring the machine back with only one group working, so at least I can have the use of it over Christmas.
Anyway it's not all bad. I've been having an interesting time refining my press-pot skills and roasting light for brewed coffee. (That's called putting a brave face on things
)