I think this is a difficult place to ask this question, because people posting on the conception thread are mostly trying to conceive. It's also impossible to say whether you will feel it's worth it. I haven't read the other thread so I can't say anything about what they feel they've lost, but if it's things like going out etc., then you will be comparing totally different types of things. Having a child is starting a new relationship with a person, so it's like saying would you rather have your mum / sister / friend or would you rather be able to go to the pub five nights a week. They just aren't the same sort of thing.
I've got one DD, who's 4. She is the best thing that's ever happened to me, and I include meeting my DH, who I love very much, in that. It is amazing to me to watch someone grow and develop, learn to speak, tell you their ideas, find out about the world, spend time with you.
I was a pretty stressy person before lots of 'to do' lists, and having a small child forces you to live more in the moment, sit and draw with them, sit and feed them, play at the park, listen to what they did in the day. I am much more relaxed now, and I think I know what the priorities are in my life much more clearly, in terms of being loving and supportive to my family and friends, and forgetting about whether I'll have time to get those shoes in Topshop, or whether I should be improving myself with another course. These things do also matter, but it's just that they don't matter as much. And just like I get fed up with my mum sometimes, I get fed up with my DD, and I need time away, which is normal imho.
I also think that the first six months is very hard, a big culture shock and a bit adjustment to doing things for someone else before yourself every time, which most adults have never really had to do before (certainly I hadn't).
I'm pg with another one now, and despite having a mc last year and trying for a year with this one, I still have uncertainties - will they be more difficult? Will the two of them get on? Will I struggle to cope? You don't know what your child will be like, whereas you do know your life now, so it's hard to take a gamble logically. With DD, we tried because we wanted to instinctively, and I think that's why most people try. We also tried because we thought about what we'd be like in ten years' time if we didn't have a child, and we both felt that although we liked our lives, we didn't want to be doing the same things forever and ever, and that our relationship would probably become quite stale if we were. So those were the deciding things for us. I think if you want to, you want to and, all other things being equal (e.g. you're financially stable, DP wants to etc.) logical arguments for or against aren't going to result in a satisfactory decision. Good luck with what you decide.