If you want to know about quality, I'll start by saying that a lot of people conflate quality with preference. The subject matter, posing, decoration, etc., is not something that can be objectively assessed. You'll have to figure out what you prefer in a mini for yourself, as you're the one who pays for it, works on it, and has to look at the finished product. Manufacturing quality, on the other hand, is a pretty objective assessment, so I'll go on about that.
Generally, look for these things when determining quality:
What kind of material is it made of?
- Is it lead or mostly lead, or one of the lead-free alloys? Plastic? Resin?
- If it's metal, make sure that it isn't discolored or starting to tarnish; either of these indicates QC problems in the casting process, or possibly even in the selection of casting materials.
- If it's plastic, make sure that you can't easily score it with a fingernail. Some companies use cheap, soft plastic that won't stand up to the rigors of painting and playing.
- Resin is generally good, but remember that resin dust is toxic, and can cause cancer if you inhale too much when filing and sanding it.
Second, look for casting problems.
- Are there mold lines? If so, do you think you have the skill to shave them off past whatever details they cover?
- Sometimes the casting mold will actually mis-match the two halves, with one side higher by maybe 1/16" or so. This creates something like mold lines(someone help me with a proper name here), but it is far harder to fix; if it is severe, simply insist that the manufacturer/retailer give you a new one. This is my main problem with reaper, and is why I have stopped buying their stuff unless I can see it before I buy and know it is cast well.
- Are there sections that look pitted, like someone dropped a caustic onto it? This is called pitting, and it is caused by a lack of sufficient material or trapped air in the mold (usually). A high number of models with this defect is usually the sign of a cheap operation.
- How about flashing? A fair amount of flash is normal for many models, but it should never be hard to remove. GW is particularly bad with this, often leaving giant tabs on delicate places that need to be clipped, ground and sometimes sculpted over, or leaving small points on hard to fix places like ornate kneecaps or boots.
- While I like resin, you need to watch out for air bubbles. This is unavoidable to some extent, but you should not be essentially required to re-sculpt the figure when you file them down and fill them with putty.
Finally, I look at ease of assembly:
- How easily can you get the joins to meet properly? Are there always large gaps between body sections? Metal GW horses are terrible when it comes to this, almost always requiring a fair amount of superglue and putty to fix the gap, and then sculpting to hide the seam. You can't always avoid this problem, but with some companies it is an endemic problem.
- How sturdy are the joins? I had some old metal Rackham Gryffon duelists a whiel back, and while I loved the sculpts, they had the most terrible configuration for the components. The body came as one solid piece except for the hands holding the swords. The spot where they joined was tiny, was not socketed or any other thing else to make the join solid, was too small to stick a pin into, and was designed to be cantilevered out so that the slightest pressure on the sword would snap it off, no matter how much glue you used. Even the folks here told me in effect: you won't be able to play with them."
- What kind of base does it have? The Reaper "broccoli bases" (you'll know them if you ever see one) are simple and effective, but a total pain to remove if you want something different. Slotted bases are nice, but many companies will make the tab on the mini too big (requiring cutting and filing just to get it in the base) or too small (requiring shimming or puttying to keep it put).
I hope this helps. If you want to talk about preferences at any time, however, I'm more than up for it, as is almost everyone here. Feel free to PM me, or start a normal thread asking for opinions on certain pieces or lines.