I also notice that I now suddenly get messages from something called McAfee WebAdvisor, i.e. once again they installed software on my computer without asking or telling me.
Sorry to hear that - it would be a disqualifier for me too. Luckily my PC was spared the third party interference.
I haven't noticed the file size issue, as I normally download at max 720p, and find the duration of the video gives a good enough estimate of how long I'd sit twiddling thumbs. But ja, file size would conceivably be a handy additional feature. I might just suggest it as an improvement.
Waiting for the file to download isn't the issue; running out of data is. I have a limit on how much data I can download per month. On the last day of the month I make a point to use all of it, and then I often download movies that can take hours to download. :-)
Which brings us to the other great web thing besides YouTube, namely Pirate Bay. But of course we are all too nice to ever use it... :-)