I've never had any major problems with it apart from not maxing out my connection but there really shouldn't be any issues this time around.
After all, Virgin are the official ISP partner of the PS4 and according to a Virgin exec there will be "loads of exciting benefits for customers". What these are remains to be seen however and it may amount to nothing much but here's hoping it's decent.
Source
I did have some big problems with them when I used my PS3 with wifi. I'd only get an absolute fraction of the speed I should and reading around it was a common problem for VM customers.
That said I left it for a year or so and booted my PS3 up for the first time in ages to play GTA5 and it does seem to be better, although I'm using a wired connection now.
I was going to hold off buying a PS4 until I heard how PSN was with it, but seeing as how VM have partnered up with it, and because I'm too impatient, I buckled.