Let me start by pointing out that while I have used an Elektra Semi extensively I have only read about the A3 and T1 before this so I do not have first hand comparisons. Also I will comment that mine is too new to me for me to be reviewing it from a quality of espresso perspective (but it is easy to observe that the steam is great). If people are interested then soon I'll be happy to add posts with impressions, but this first post is mostly about concrete facts. I hope other new users will also add lots of info.
Here are differences that I have observed...
1) Most obviously a major difference is that there is no longer a manual A3 option.
2) The plug on mine is a 15 amp plug(?!?)
3) The cup warming tray is no longer super hot, unlike Dan's review model - in fact I have to find a cup that is the hottest because many are close to room temp and even the hottest are not very hot. Perhaps related, reading Dan's review it sounded to me like both layers of his warming tray had vent holes in them, carefully lined up so drips would be caught in the lower tray if not in the top one (or carefully not lined up as it were). On mine only the top tray has vent holes, the lower tray is a solid sheet.
4) Perhaps I am just coming from the Pavoni/ Elektra Semi - exposed boiler camp, or perhaps it is because it is winter so warmth is not a negative, but the rest of the exterior of the machine just does not seem that hot to me either. I heard lots of comments on the heat coming off of the machine being extremely high, but if, for example, you touch the side of it you do not pull your hand off quickly in fear - a feat I would never dare try on my previous Pavoni or Semi. (And yes the boiler inside is plenty hot - it takes a serious flush to get the water to the right temperature for espresso, especially if you have not been pulling shots recently - I'd guess 8 oz if you have not used it in a while and perhaps more - I think roughly twice the flush of the Semi when it has not been in use).
5) Aesthetics - the old one looked good and so does the new, but the new one looks a little different. It has a slightly different font. The buttons look a little different.
You can see the old one here in this thread
Opinions sought: Elektra T1 vs. Cimbali Junior DT1 vs. Vibiemme DoubleDomo Super
and the new one here

I like the new look, but liked the old one, too, based on pictures.
5) Drip tray - the machine comes with two different racks that fit in the drip tray. One is low, one is high. You choose one at a time. I can upload a picture of the two if you like. The pictures I have seen all show the low drip tray, the high one is an inch or two higher. The high one is great for espresso, but makes pointing the steam wand at the tray a little cramped when you want to purge it before or after steaming. I'll probably just use the low one. I do, however, think the raised drip tray is a better idea than the portafilter extender they tried before, that Dan mentions removing in his review, but the extra clearance from the group down to the tray is not a major issue since again if you want to pull a shot into a short cup you can flip over a cap cup and sit it on top.
6) Steam - it is a glorious steamer, but I wonder if it is a little slower than the old one. I have no trouble creating microfoam with 4oz and I was a little worried that going under 6 oz might be hard (but I love commercial steamers so it isn't shocking that I love this one). It seems to be fairly fast and have copious steam for those who like big milk drinks as you would expect from such a large boiler but well within the range a home user who likes small milk drinks would like (I don't drink big milk drinks usually, but I did steam a huge pitcher of milk for hot chocolate today for my kids and it was a joy and there was no sign of the machine slowing down).
One note on taste that is more about a non-change - You still need a pressure reducer as Dan pointed out in his glorious review. My house's water pressure was too high and so today is the first day that I have had the machine configured properly so I will refrain from passing any judgements on espresso (although today I pulled some nice shots as I dialed it in, so I am hopefully optimistic).






