So here's the thing - they're not actually that good. Let me preface this by saying that a) my perspective isn't a normal consumer one -- my business has put tens of thousands of miles on various Aston Martin models (we rent them) and b) the last model I've dealt with extensively is an '06 DB9, so things may have changed a lot in the past few years.
But that being said, despite being IMHO the most gorgeous cars on the road, Astons are not particularly well-engineered.
First, we had an '02 Vanquish and an '03 Vanquish, both of which had a very fundamental and deeply expensive flaw in the transmission design. Without getting too deep into it, they used a "auto manual" style transmission, which was basically a 6-speed manual combined with hydrolic actuators to shift automatically. No manual clutchwork required (same design, basically, as BMWs SMG). On just about all similar cars, after a while (i.e. 12k - 15k miles) the clutch needs to be replaced. On Ferraris and Lamborghinis, it's a simple job that costs a few $thousand - drop the transmission, replace clutch and flywheel, and you're good. On both the Vanquishes, the way in which the clutch would fail would literally destroy the entire transmission, and we TWICE had to spend $15,000 to rebuild the entire transmission after a failed clutch (one on each car). I've never seen another car with design like that, and since it happened the exact same way on two different cars, we're pretty sure it's endemic to the design.
Move to the later models - we had a bunch of 05 & 06 DB9s, and they just weren't great. The brakes were notoriously bad, the bodyflex was particularly bad on the convertibles, and they suffered repeated electrical gremlins.
So from my purely technical perspective as a heavy user of Astons, I'd say I'm not impressed with their engineering.
NOW - that all being said, I'm not going to make any judgment about this guy and his work at Tesla and what this means about that. There is far too much that goes into the production of a car to make any real judgment call about things to come -- Astons could have been beautifully engineered and then ruined with bad supplier decisions, that were outside this guy's control. Etc. etc.
So them's my $0.02.