Hey, never expect a simple answer from me. I've been around since before the release of City. So, there's an obligation on my part to overexplain and use some of that fanboy knowledge I snagged.
As for where to start... it's tough to say really. That depends a great deal on what you like. To make the long story short... SYL's "Heavy as a Really Heavy Thing" was the post Relativity screw job I-can't-believe-I'm-signed album so it's all over the place and has a demo-y feel to it. On "City", he focused a bit more and purged a lot of bile to tune of crushing "industrialized thrash". That was followed by Ocean Machine's "Biomech" which hinted at a problem in that it was down right mellow and even beautiful in parts. After that, the two sides went out of control and the musically ingenious but absolutely daft "Infinity" was born. "Physicist" was pretty much an exercise in recovery and was more simplified than some of the earlier stuff. "Terria" well... that was sort of the moment where Dev had control over himself back was able to sit back down and write focused, quality, music without tearing himself apart.
Personally, I prefer "City" "Biomech" and "Terria". They're a trio of really well crafted albums. "Infinity" is very dense and downright ugly on many levels. My aversion to it has nothing to do with the music itself. It's just that it came from a hideous period in the man's life and alot of what was going on with him can be heard.