I'm a big fan of Mirage models!
As you said, plenty of really interesting subjects. They were 'first out' with a 'regular'-production 1/48 injection-molded Halberstadt CL.II -- one of those life-long 'wish list' kits I wasn't sure I'd ever actually see -- and theirs was exquisite. I've built probably a dozen or so of their 1/400 ships...the V.106 WW1 German destroyer (also sold in several post-war Polish navy versions), and their gorgeous range of assorted marks of the USN's WW1-era 'four stacker' destroyers (which also saw wide service through WW2).
Their level of detail can tend toward the uber-excessive -- such as 2 or 3 parts that need to be assembled to make a simple part like a 1/400 lifeboat davit, that could easily be molded as a single piece -- and is aggravated somewhat by a plastic that tends toward brittleness, making clipping and cleaning up tiny parts an ongoing adventure. But that 'uber' quality doesn't extend to every part, just crops up in odd instances.
Overall, the quality of their molding is generally good to excellent. [The one continuing exasperation is a quirky one -- they seem often to position the mold attachment stubs on the 'detail' side of parts, rather than the flat side that would make cleanup so-o-o-o much easier! Ah, well...]
If you're a ship modeler, their 'multi release' kits (like the four-stackers) are a treat -- stuffed with all kinds of spare and alternate parts, extra gun fit-outs and such that will make your 'spares' box happy.
Their decals, at least as I've experienced them, are also superb. For the Halberstadt kit mentioned above, they supplied the unique multi-color fuselage mottling applied by the factory as a single sheet decal to be cut and fitted in place...over multiple compound curves...and everything worked perfectly, with little setting solution needed, for a really exquisite effect. Whites on tiny fuselage inscriptions were perfectly opaque, and registration of colors on insignia and such were perfectly centered and aligned.
The one thing I can't speak to is dealing with ordering and shipping from them, since I got all my kits through Hannants or US distributors. But judging by the way they do everything else, I suspect they're probably 'on the ball' there as well.
Cheers