[Verizon Motorola Droid Turbo General] adrynalyne:
What is the knee jerk reaction to:

"Name the differences...."

vs.

"What are the differences?"

First example is full of snark and challenge, the second one is asking for knowledge. Now if English is your second language, I understand. If not, you knew full well where you were going with this. That said, I'll humor you and assume you meant the second.

The theme was somewhat finished, yes. There were still Kitkat elements all over the place though. At the time, there were nearly no material themed apps of course and themes mean nothing overall. Here are the real differences from the original dev preview:

1. Compatibility sucked, likely due to an unfinished ART.

2. APIs were not finished, which likely led to the compatibility issues.

3. Stability was at an all time low.

4. System functions did not work at all such as cast to screen.

5. In the poster's case, he was using Kitkat blobs to limp along with a Lollipop preview.

6. Debug code was everywhere, slowing it down.

7. Edited: The original preview was for the Nexus 7 and Nexus 5 only, which means it wasn't optimized for other phones at all (yes that is a thing, done by the overlay).

8. It had nasty bugs, especially with Wifi and battery drains.

9. It was actually missing framework resources, which relates to 1 and 2.

10. I don't even think encryption worked, though to be fair I never looked.

Those are just a few things I noticed. Now I know that people like to say, "hey, the developer who made my Lollipop rom fixed those", but being that I have played the modder game, the rom game, and now the app dev game, let me shed a little bit of reality on that:

1. Those who work with pre-compiled software are modders. They tear apart and try to reverse engineer parts of roms by decompiling and trying to figure out byte code. To make a change, they modify byte code methods to make certain functions behave differently. They will frankenstein roms together with pieces of other roms from other phones or variants to fix things as well. Then they re-compile the byte code back into something usable. The results can vary from awesome to horribly broken. In many cases, those breaks are not at level that users see. Logcats blow up over them though, and you see just how much actually broke. This will many times break digital signing as well, though sometimes you can skirt that. Broken signing leads to nice fat security holes in an OS that really doesn't need help with being insecure. The problem with the Lollipop DP is that there was no spare parts "junkyard" for modders to use, and no way to compile it from source for new spare parts. The next problem comes from the blobs used. Due to the nature of the DP and it not being for phones, that means that for many phones, Kitkat drivers, resources, and radios were used. That means it supported none of the new under the hood performance improvements of Lollipop, was not optimized for what new APIs were there, and in general "feels" like crap because it runs like crap. It was a hobbled together mess, regardless of modder who did it.

Hence my hacky garbage comment.

I know exactly how porting works, because I have done it myself. Heck, I did it for the OG Jellybean DP for the Verizon Gnex (pretty sure I was one of the first too). I took it to Cali with me. It was fun to play with! However, my phone was so utterly broken, I was forced to use VZ Navigator. That was from the GSM variant to the CDMA variant, so things were mostly the same except underlying blobs. Imagine if it originated on a tablet instead? It was a garbage port, and so were the others out there. When final JB came around (I compiled it from source), it was WAY better. Comparing the Lollipop DP to the Jellybean DP, the latter was far more finished too.

Disclaimer: I am referring to the original DP, because a poster was acting like he had truly been running Lollipop for 6 months as if it were final.

In reality, it was a hack job of unfinished software and is a moot point. There was a second DP, but that only added wear support, and did not address the rest of the issues. The third DP added more phones and had finished APIs. It also was mostly bug free and performed much better, though there were some last minute changes from Google before production release.

tl;dr version:

Lollipop from 6 months ago was an old Honda Civic with a bad paint job and body kit dragging on the ground trying to look like a Corvette Stingray.