I thought it was average at best. I've taken long-distance sleeper trains all my life, but the Caledonian Sleeper has rubbish breakfast, poor bedding, and you have to exit the train right after it arrives.
I mean, one of these three is fine, but all three and it was worthless for its objective. It costs a hundred quid and this is what you get? I could take Virgin for half the price and be there in 5 hours and actually sleep in my own bed instead. It's what I'll do next time.
I suppose the one plus is you get to use the lounge at the station, which is about the one place that Waverly Station has plug points for a charger.