Sales staff will sell you what they have. Even with 30-day returns, typically you get a store credit, which you can apply to another machine, many times ending up being more expensive than the first ("Well, if you didn't like that one, this one for only $300 more should address those considerations").

The Silvia has a great reputation, in my opinion, as it was comparatively cheap, somewhat better built than its competition at the time, and then it was "discovered" that you could add a PID unit for a couple hundred dollars to get over its temperature-control problems. It gained a following on Usenet and the coffee boards, which spilled into the mainstream with blogging and social media. As I recall, it has an OPV which your machine may not, which controls brew pressure, which would be a step up from your Gaggia. The change in basket size to a "standard" 58 mm is interesting, but not one that will dramatically improve the espresso. While it may have a tighter dead band to its temperature, without a PID you'll still need to "temperature surf". The reliability of the Silvia-E and its electronic controller is an open question. Current retail looks to be $735 without PID. A PID kit bring it to around $1000.

I have used a Silvia at an away-from-home location and "consistent" isn't a word that I'd use to describe the results. The best shots with it, when I was lucky enough to get them, were on par with my mediocre shots from my HX at home. My better shots at home were much better than those from the Silvia. I had access to a Silvia at work. I ended up deciding that the coffee out of the industrial coffee machine with enough milk or cream was a better bet.

The ECM Casa V at $1000 looks to be little more than a fancy Silvia. Its still a single-boiler unit and without a PID, as far as I can tell. At that price, I'd go with a Quick Mill Silvano ($1075) which gives you the PID control to better regulate your brew temperature without surfing.

The challenge for me is that, assuming you can still pick one up at the old price of $1,200, the BDB provides just about everything you'd want in terms of temperature stability and control, pressure stability (or control, with simple mods), and preinfusion control. It then adds in a quick warm-up (perhaps as quick as 10 min) rather than the 30-minute warmup of the single-boilers discussed above. It's a machine that I think most would agree they'd be able to quickly dial in shots and reliably get good to great espresso from. Even at $1,500, my assessment is the same.

HX machines have a certain aesthetic appeal, but they require their own "surfing" methods (flushing) for temperature control. The Lelit MaraX (note the "X") is an exception to this, with it clever control system, but it is at $1,450 and I think the BDB is more stable, more flexible, and can produce better espresso.

I think an option worth considering would be the Cafelat Robot, an electric or stove-top kettle, and using your Gaggia for steaming. They run around $400, depending on options. Manual levers can be very forgiving, as you can adjust the flow by pressing harder or softer as you go. Temperature control sufficient for medium and darker roasts is basically pouring boiling water into basket, pouring it off, refilling it, and pulling your shot. There's an in-depth review at Cafelat Robot Review and a really, really long thread around experiences at Cafelat Robot User Experience They're compelling enough that I've tried to pick one up used (they resell very quickly), and will order one either when the polished ones come available again, when HK-to-US shipping gets cheaper (since I want some non-stocked accessories), or when my desire outstrips my patience. Prima Coffee should be getting restocked shortly. They are also available through IDrinkCoffee (prices there in CAD, about 0.76 USD to CAD, they ship "free" to the US, from what I recall).