I do think there are some costs involved with SPC (semi-private care) but combined care is completely free and as a good a service as SPC. I've actually known the queues for the SPC clinic to be longer than for the public in Holles St.
If you can go with the Midwives, I'd highly recommend it.
If you can't, try and go to a satellite clinic close o where you live. I attended the clinic in Wicklow Town, never waited longer than half an hour to be seen, and was seen by my consultant at every visit. People pay thousands for that!
I honestly can't understand why the 'Prvate' system exists. I know couples who do go private have their reasons and thats their business. But if a problem arises in a pregnancy, the treatment is the same regardless of what level of cover you have, and infact, going Private won't buy you a private room if you need admission antenatally! In the UK and many other countries around the world, there is no need for a private system. But anyway, this is a whole other topic
If you do decide to go SPC, you may get a bed on a ward with max 5 beds in it. In Holles st the public wards have 6 beds in them but occasionally they have to squeeze in extra beds. And of you have an epidural or need a section or anything, the Insurance will pay the consultant for this service whereas if you go public they don't. (well they do but only as part of their every day work!)
Oh and Congratulations