I did it a year ago - was called before the new jurors' briefing had finished, was selected to sit, and the case lasted the full 2 weeks.
I found the whole thing fascinating - the process, the formality... every day it was like stepping out of the normal world into this bubble. They way its done, with the evidence, witnesses, cross examination, judge's summing up, and then the jury deliberations, does make me have confidence in the system. As a PP said, you are probably more likely to get an incorrect NG than an incorrect G - the judge really does emphasize the need to be 'absolutely sure'.
The case was horrendous (historic child indecent assault and rape), and I think we came to the correct verdicts.
The only thing I had strong feelings about (and I have chewed the case and the process over in my mind a LOT since) was that the defendant's life experience, his background etc., was always going to end up in the criminal justice system. It was depressing for me (a middle-class professional type with lots of opportunities and choices from day 1) to be confronted with what life can be like for some families as I very rarely come across it. Without taking away from the crime he was convicted of, I did feel sad that the system that was clobbering him now wasn't a system that was able to intervene at an earlier point to prevent it happening.
The other thing was the jury. I was foreman and we had a hugely diverse selection in every which way. But there were a couple of people who should not have been on a jury - one with offensive views on how and why girl children are sexually abused, and how they should behave afterwards (whatever you are imagining, it was worse), and one who was so incredibly naive that they thought there was no need to convict because all concerned had probably learned a lesson and they could all go away and have a beautiful life.... So, while the majority took it seriously and were normal and conscientious, I was reminded that the general public does include some very odd people who really aren't appropriate to sit on a jury. It's a good job there were 12 of us really!