It seems that my PhD experience in EE (semiconductor devices) was better than most. I loved it. I worked on interesting stuff, and I worked for a professor who is at the top of his field. I did good work on interesting projects, and I still do work similar (but less interesting and with much less freedom) to what I did in grad school. I actually miss school because I miss the freedom to just do interesting work.
Grad school is free. They pay a small stipend (~$20K), but it was enough. I went straight from my BS to grad school, so I never had a taste for money or furniture or a decent car. I think it would be hard to have money and then go back to school, but that's me. The stipend was enough for me to travel overseas and wander around Asia ($15 hotels in Thailand beach towns), and I had the time while in school to take off for a couple of weeks and do stuff like this. My boss was cool, and I worked hard the rest of the time so he didn't mind.
I walked out of grad school and into a six-figure salary... you know, because I'm awesome... but pretty much all the guys in my group are at least in the mid-90s, so don't think it's a total financial let-down... at least not for everyone. I mean, it's not lawyer or doctor salary, but it's alright.
The biggest reason that I did the PhD is because I value freedom to do interesting work. I did internships to pay my way through undergrad, and I saw what engineers do. It wasn't too interesting. I prefer research (or at least development), figuring stuff out, creating something new, blah, blah, blah...
PhD. Totally worth it. I'd do it a hundred times over.
YMMV
BTW, I still publish, and I keep up with what others do mostly through journals and conferences.