They're odd ones alright. Blues prices are pretty good, but I think boxed complete Daimakaimura is a bit more than that.
I've seen all the SGX games apart from 1941 unboxed for around £10, and boxed, Aldynes, Granzort and Daimakaimura for £50-£40.
Battle Ace is cheaper, and the only one I don't have (1941) is just too rare and too expensive for me to bother with for what it is.
Haven't played much battle ace, Aldynes seems fairly run-of-the-mill, and Granzort and Daimakaimura are the good games.
I got my SGX boxed complete for £90, but I've not seen one at that price before or since.