Well I've owned a lusso for about a year and a half so far and yes I'm really ready to move on. It's made some great coffee's but another machine has caught my eye, and I really want a commercial lever.
Jack from Sorrentina has been fantastic, but in my opinion Ponte Vecchio really dropped the ball. From day 1 I had a leaking group due to scoring in the cylinder. PV said they would replace it, but they forgot to send it with the first shipment, and then finally it was sent with the next one. Would you believe they send Jack a single group which is different to the twin group machine! Jack only orders the twin group machine!
Jack gave up I think and gave me one of his machine which was nice of him. That took 8 months by the way from start to finish!!!
Anyway, I finally have it working now, and I do love it in many ways. I've modified mine to have an antivac which has made the machine much better to use.
Regarding shot volume, I have never used a single basket with this machine. It's tiny! I use the double, and give about 10sec prefusion by pulling the lever down, and just before the water is about to enter the cylinder, I lock the group handle in. I usually let the lever rise just slightly, then push it back down. If you let it rise to the top you'll get a lovely espresso, around 10-20ml, and if you do another pull you'll get around 30-40ml ish. Depends on grind.
check out my mods thread here for more info. http://www.bestcafes.com.au/forum/projects-rebuilds/ponte-vecchio-lusso-mods/
Also there is a thread or two on CS, one regarding changing the seals with Jacks tool, and another just about general lusso use.
My machine will be for sale very soon, if your interested. I still have the box. It's got 4 custom timber handles, antivac mod, and bar a few scratches on the drip tray and a few on the lid, it's in good condition. Also one handle is nakid
Hope that helps. There are plenty happy users out there, and it's a great machine. Even though everyone says it looks like a toy, it can produce the goods. Milk is great one it. Not to fast, not to slow.