As others have commented, the total lack of anything Irish in the past is what is worth bearing in mind. The model looks well proportioned as far as it goes, and while not cheap, Mayner's point about a "proper" kit being a lot dearer if bought RTR is quite right.
If the proportions weren't right - e.g. it's way too tall or short or something, then we'd have good grounds for ignoring it, but as others have mentioned, lacking detail can be remedied. Wrong proportions can't. Again, as yet others have mentioned, we may be spoiled by the sheer array of Irish stuff available now - there must be, what, a dozen people on this site (plus Worsley) making various stuff suitable for Ireland.
I'll be the first to admit having criticised some of it, but that's usually over livery which is the easiest remedied detail of the lot! And to those I appear to criticise, in fact I admire them for putting their head (and efforts) above the parapet. As one who came from a career financial background, I don't have to be one of them to be able to point out that these people aren't in it for the money - these Irish models are break-even stuff, often funded by the one-man-band-maker's own personal finances.
So, overall, while I won't be buying one of these - simply because it doesn't fit into anything I'm planning, no other reason - I congratulate OO models, whoever they are!
If I was planning a model of the Bundoran branch in 1956 (now, THERE'S a layout idea; steam and scenery!), I'd probably break the bank and buy a couple....!