At the end of the day, the HSE are mad to get the elderly out of hospitals - between them and people with elderly parents they can't look after themselves, there's a definite market.
What I'd do is check out who's actually going to be running the nursing home and what their pedigree is. If they're newbies to the business who were flipping burgers one week and trying to this, this week, I'd avoid the place like the plague. If they've a history in the sector and know how the health boards etc work, you're onto a better one.
It seems as if in the last few years, builders opened these places and tried to run them themselves with no idea of the business - not a recipie for success.
It's the same as anything I suppose, if you reckon you'd be happy to have you're granny living there, then it's probably going to be successful.
Regards the returns, this place from what I can see guarantees the rent for the first few years, which is a definite bonus as it'll probably take 12 / 18 months to fill up - section 50 campus work on the same premise.
Regards the saturation issue the tax breaks for these places have dried up as well so you probably won't see too many more being built, so saturation shouldn't be an issue.
And in fairness, even if there are a few, in 15 years time the places should be well established and showing a strong history of return so punters will know exactly what they're getting.
Just look at the lads that bought section 23 15 years ago..
Here's the link to the Dennis O'Brien piece I mentioned before.
http://www.rte.ie/business/2004/1020/barchester.html
When it comes to investment, if you were going to follow anyones lead, you'd definitely do worse than him!
Hope this helps!