I prefer Irish National because it is a brighter green, but there are other people who prefer Ireland's National for exactly the same reason! I've always liked bright colours, but not everyone does.

Frugal Corner, as well as several eBay vendors, sell Irish Heritage, which is another similar tartan. I wasn't very happy with FC when I bought my solid green kilt, though.

As you say, there is also All Ireland by Locharron, which is quite different, but most people have only seen that in the Green version, and in fact there are Blue and Red versions as well. I believe Rocky commented in another thread that one of his personal kilts is in All Ireland Blue.

None of the above go back very far. The St. Patrick tartan is older than all of them, but even it was only registered in 1971. It has similar colours to most of them, but has large areas of white, which is normal for saint's tartans (as well as for dress tartans). There are several sources for kilts in this tartan, even including Sport Kilt.

There are a couple of other setts that are older than St. Patrick, such as Eire and Special Saffron, but good luck finding them! Burnett and Struth has "O'Saffron", which is actually the tartan of the Canadian Irish Regiment, and is similar to Special Saffron, but is not the same sett. I rather like the look of the Eire tartan, but I don't know where you could find it.

OTOH, Irish kilts in solid green date back to c. 1890, and solid saffron Irish kilts go back as far as 1857, AFAIK.