At 238 MB, it seemed rather small for the length of time waited for performance fixes. I was expecting something three times the size. Then again, when I first downloaded iOS 7, I was on my iPhone 4s and now, I have an iPhone 5c.
The brand new iOS 7 really downgraded the performance of the 4s--no, not to the sad level of the iPhone 4, but it was truly disappointing. I had a game at a critical point and the phone was lagging badly, trying to run the game, and there was no chance of succeeding.
For those using an iPhone 4, it's likely safe now, but not a final step. I was remembering my second generation iPod touch and how iOS 5 had killed the performance. iOS 5.1.1 brought the device back to life, but I think it wasn't until 5.2.1 that it was actually almost as good as the previous 4.x version. It never fully recovered. I suspect more performance enhancements to make it before iOS 7.x is finished.
It looks as though there were a lot of little tweaks that they didn't quite finish before sending iOS 7 out the door and they've included those now. I don't recall anything in particular but it looks a bit more integrated already. Performance seems enhanced but not supremely fast. At least, nothing seems to have become worse...yet.
Update 2014.03.19: I guess I'm lucky. I'm new to using iOS 7.1 as a mobile hotspot and it seems to be just fine. I guess I spoke too soon. If I don't leave the hotspot functionality active, it isn't so good. There is trouble with the MacBook Pro finding it after a few times, and I have to re-boot the phone. It seems to occasionally connect, if I go back to the Personal Hotspot display, without re-booting. Those who were using the functionality prior to 7.1 are experiencing issues. In an episode of He said-She said, Apple is not taking responsibility, and naturally, the carriers are not.
At least, there will be another update before iOS 8.0.