Shambles? That's a little strong and inaccurate. The network has been fine for the most part, but there have been issues.
PS4 and PS3 use different pieces of the PSN network.
Personally, I think it has been. It's *much* worse than it was before.
For example, I have a 120mbit internet connection here, and can't download a game from PSN at more than about 5 - which makes downloading a 20 or so GB game very difficult. It frequently goes down with no explanation from Sony (e.g. yesterday the store was down, but the status page said everything was up). With the exception of the old security breach, PSN was pretty stable. In the last 2 months I can recall at least 8 times when I've not been able to use it - and I'm not exactly on my consoles 24/7 - so I guarantee there's ones I've missed.
Heck, the other day, it took nearly 10 minutes to download my LBP game save (50MB) from PS+ storage. I also quite often see messages about failed save uploads on my Vita in the morning.
I don't expect it to be up 24/7 365 days a year. But given that it's now effectively a paid service - I do expect higher levels of reliability and at least a correct status page when it does go down.