I have a Cybergun/VFC AEG Scar-H. It's a nice gun with good externals but the mags are expensive to get a hold of (about £15-£20 per mid-cap) from Asian retailers. I haven't worked on it internally yet but i've been told that VFC internals on AEGs are pretty shit. IIRC it has a standard V2 gearbox meaning upgrades are plentiful and cheap. The only parts that aren't standard are the hop unit and nozzle (length is like 35mm or something) but Maxx make a CNC rotary hop unit for Scars that will fit the H apparently.
You'll struggle to find one new at a reasonable price due to trademarks and availability - The only retailer I know of with them in stock has them priced at 400 euro. I got lucky on the forums here and snagged it for about £100 plus £20 for a replacement part that was missing.
Double Bell make a Scar-H which has no trademarks making it cheaper than other AEG Scar-H models but the magazines are still pushing the £15-£20 price range area but with the RIF being £200-£250 it's still a significant investment. I can't comment on the quality of the internals having not owned or worked on one.
Personally, i'd suggest looking for a second hand one as you may be able to get a rifle + mags but from what i've seen they rarely come up for sale. Even when they do come up, unless you get really lucky, they're great examples that have been cared for, upgraded and the owners demand a good price for them.
If there's anyone super knowledgeable about AEG Scars reading this, i'd love to pick your brains over some stuff. Please PM me.