Totally worth it in my experience, if anything to meet other local women who are in the same boat! I finished mine three weeks ago and have met with the ladies for coffee now I'm on mat leave; we're also going to meet up after birth. It's nice to have that option of a support group, meeting new people etc, when you go from working full time to finding yourself at home.
I went with my DH and we both found it helpful to go through the various stages of labour in a setting where you can ask questions.
People have different experiences of them, which I think depend largely on the group of women who attend and how much you invest of yourself.
Hypnobirthing is a specific method to deal with the pain of labour so I wouldn't recommend it, instead find a more general one as local as possible, preferably led by local midwives.
I did the NCT ones for our first baby. There is no comparison between those you get on the nct and the nhs. Also we had our own antenatal group which we met up loads with after the babies had been born. Dh felt more part of the nct classes to and so bought us together as a couple. There are loads of types offered so. You will need to book them fairly early as they fill up quickly.
Where are you? I've been doing Lazy Daisy in the NW and it's been ACE, really enjoyed them, plus having some time to spend on me and concentrate on this pregnancy (have toddler DD so it's nice to be able to spend some time thinking about the new baby occasionally!).
I didn't do NCT ones first time around because they were full and I'm kind of sad about it as it would have been a good way to meet people. I haven't done NCT ones this time round either but I did observe a course as part of my NCT breastfeeding counsellor training. I'm not sure it would teach you anything you didn't get from books etc but they looked really fun and the two big pluses imo would be getting your partner to learn something (I bought my DH a few books but he didn't read them!) and meeting other local parents. Haven't bothered this time round because I don't think I'd learn anything.
Would say the two are completely different (from what I've seen anyway) - LD is more focused on you and getting your body ready for birth, relaxation, active birthing etc, much more yoga based, whereas the NCT ones I've seen have been much more focused on eg pain relief options for labour, parentcraft like nappy changing, breastfeeding, how your relationship will change etc with very little physical exercises or relaxation, so depends what you're after.
To be fair my memories of hypnobirthing are a bit fuzzy now, 2.5 years later, but from what I remember all the useful bits of hypno come up in LD anyway (though it's possible I only notice them because I did hypno as well iyswim)