When it comes to miniatures, I'm generally a person who likes a few different things. Primarily, they have to fit into my role playing games. Most of the Privateer Press miniatures don't often fit that criteria but... I was one of those people back in the day that had the Iron Kingdoms d20 version and used quite a few things out of it.
Not only that, but my friends tended to run 'gonzo' style games. So while someone may have run the Scarred Lands or Swashbuckling Adventurers, they did so with a lot of leeway as to what was allowed. It may not have been 'purist' but it did allow a ton of variety and enjoyment during the 3.0/3.5 years.
In terms of 'thinking' about an army to build, I've always tended to buy here and there based on visuals and background. The later is highly unusual since I don't actual play but...
Looking over Warmachine, I didn't like Cygnar. They were a little on the 'goody goody' side and well, I'm not a huge fan of the color scheme. I know that's lazy but since I usually go with the 'traditional' scheme for ease of reference and to hasten painting, that's the way it is. The Protctorate is another one I didn't like. Religious nuts are best covered in ye old 40K. Cryx has some interesting models and I like the whole concept of undead mechanical horrors but a lot of it doesn't grab me.
Now that's not to say I couldn't find points enough to field a 15-25 point group in any instance. One of the things that Privateer Press ahs done well is make enough interesting models that I could easily field a small group with those factions.
I loved the Khador group mainly on it's use of strong reds, large war jacks and the whole 'Russian Fantasy' thing. While I'm not a scholar of such mythology by any means, it was always neat seeing 'the old witch' and other nods. They also did a fantastic job with one of the first war jack war casters and one of the 'must have' units, the Behemoth.
My other enjoyment comes from mercenaries. Ironically enough, that's just my preference due to reading about them and watching anime and fantasy novels based around the concept of mercenary groups. While I have Magnus and a few other figures, including several war jacks, I never really got into the lore of them although I do like how the mercenaries are essentially three or so armies in the form of criminal scum, pirate scum, and mean dwarves.
When the Retribution first came out, I was impressed. They took elves into a whole new direction and more importantly, gave them a distinctive look. Sure, there might be some crossover potential in terms of 'white' with the religious zealots but for the most part, their color and look was unique.
And now Privateer Press apparently does it again with their new book, the Convergence of Cyriss. The models we've seen so far are different than essentially any other army in the game. This makes for a great visual distinction. There are only so many times you can see the same body types over and over again.
I'll be curious to see if they follow up on this type of release. A 'Forces of' book doesn't strike me as being off in any way, shape, or form as the pirates were originally introduced in this methodology. It allows a focused fire of material to judge reaction and then can be worked on or dismissed as necessary.
It's a good time to be a fan of Warmachine.