It's about 1/72 like all of the Koto Variable Infinity kits (excluding the new Steel Haze and upcoming Nightfall/Loader 4, which are closer to 1/35-1/40) and is a bit taller than your average MG. As for it being good... well, the VI kits have always had a reputation for being a massive pain to work with, and while they've fixed some QC issues in terms of plastic quality over the years, the design of the parts and the kits themselves leave a lot to be desired; unfortunately, this kit in particular is infamous for being one of the most difficult. However, that doesn't mean it's not good: The articulation, fine details, and game accuracy are ludicrous, and this particular version of the design fixes a lot of the issues that the older ones had in terms of plastic quality and defects and also comes with enough extras and total runners to warrant the high price. I'd say if you're a big AC fan or just really like the design, go for it, but just keep in mind that it's probably going to need some patience and TLC to really shine; if you can handle that and already have some more difficult kits under your belt, then you might just end up with a true centerpiece model. (Koto's restocks usually take quite a bit longer than Bandai i.e. multiple years even for popular kits, but last fall they announced that they were going to be accelerating reprints of all of their AC kits to match increased demand in the last few years (and teased four brand-new kits), so it's 100% going to be back in stock sooner than later, maybe even within the year).

The best place would be another Kotobukiya armored core, as the whole line more or less has the same issues. Newtype currently has the Crest Lightweight in stock, which I've actually just built myself and is much easier to manage and a lot cheaper if you're worried about ruining the parts or finish. You could also go for one of the REALLY old MGs like the GP01FB or any of the G-Gundam ones (God, Master, Burning, etc.) because they share a lot of the same issues; we're supposed to get reissues of the original Zaku MGs (from 1995) at some point this year, which are some of the worst offenders. Ironically, in general the 'worst' and oldest MGs are exactly the kind of thing you're looking for if you want to get experienced with difficult models, you might even want to look into getting some really cheap aircraft or tank models for the purpose of messing around with and figuring out how to glue and paint them; you get get some from brands like Academy or Hasegawa for under $10 or even $5 so if that can save you from having to practice on a more expensive kit it might just be a good investment (but only if you have the time or space to do so, if not that's perfectly fine and you can just refer to my other suggestions.) PS: Remember this is a hobby, not a competition; don't do things that you don't want or feel the need to do solely because other people are doing so, all of my kits are pretty much 100% straight-built and I've been doing this for almost five years now; and don't worry if a kit doesn't turn out quite the way you want or you feel like you wasted an expensive or rare kit, it's still something to be proud of! (One of my favorites is the PG Unicorn and let me tell you that thing is COVERED in the nastiest nubs and gate marks, one of the ankles is broken and it needs the stand to stay upright, *but* I had a lot of fun making it and it's at the center of my collection if only to show how much better I've gotten, right next to my PGU RX-78 which I was able to make look so much better because of all of the experience I got with the former.)