Massive a la pacific rim style, nimble and athletic a la 'typical' anime style, slow and lumbering a la battletech style,
something else or inbetween?

Personally I'll go with battletech anyday, both when it comes to the universe and associated games, mech commander and mechwarrior. Haven't tried the tabletop yet, but that too looks very interesting.

By the way, for anyone with some anime knowledge, are there any animes based around mechs(/mecha?) that don't follow the, what I perceive as usual nimble and athletic style? The only one I know about is Blue Gender, and even though later on in the series the mecha become quite athletic for a skilled pilot, it's not at the expensive of a clear sense of weight and momentum.

I like them to not be too anthropomorphic. In the battletech universe, I prefer things to look like Locust than Atlas. I liked for instance the Walker from that Amiga game :

https://www.youtube.com/watch?v=VfN1cyigIM8

I liked transformers toys that didn't look like sentient robots but like piloted machines :

https://static.seibertron.com/images/toys/files/48/r_black-ironhide-050.jpg

So, basically, I don't want anything to look like a robot head, on my mechs. If anything, I'm fine with Ed 209 or Ripley's power loader. Or just AT-ST.

Oh and I also like them heavy. So, a tad sluggish. Once they start running and jumping around, they're not giant machines anymore. They're people surrounded by a mysteriously shrunk environment.

On the ground. Settings where mecha are routinely deployed in space or in the air drive me crazy. Especially when the in setting design teams waste the effort to design specialized aerial or space mecha models. You put the weapons, armor, reactor, and engines of a mecha on a conventional starfighter or atmospheric fighter and you'll get a unit that is easier to maintain, simpler to build, and just as effective during combat in its battleground, if not more effective.

The boardgame is being re-re-released at the end of this year.

Will be buying it as both me and wife played when younger and want to play it again, also our kids might like it too

Interesting, I don't really like them too anthropomorphic either, eg.
https://i.pinimg.com/originals/93/e3/26/93e3260d7942cabfa9ce0840086d6c6f.jpg
but I don't think it bothers me too much. For example I really like the blue gender mechs
https://i.ytimg.com/vi/CPwIRf4BMgk/hqdefault.jpg
and those are very anthropomorphic. Though that might have something to do with the fact that blue gender does a great job at making the mechs come across as big and heavy machines, that aren't overpowered against the monsters they face. Is it also as expensive as 40K?

Unlikely, Games Workshop has always been viciously over priced.

Also they look less than the first images' giants-in-armour. In that sense, the Evangelion EVAs were interestingly monstrous.

But, generally speaking, I don't like mech to have hands, and to manipulate objects. Even less to have weaponry (swords, handguns, etc). Pinches are okay, but I prefer the weapons to be the limbs themselves, or integrated to them.

In fact, I think I make a distinction between mechs as giant machines piloted by humans, and big robots as giant C3POs. It's like two different genres, to me. And the designs sometimes blur these lines.

Inbetween something else.

Also because it's not just classic (bipedal) mechs but also armored suits, tanks, armored and not so armored vehicles and Agravs mixing up the formula.

The whole "futuristic banana republic in space" setting as well as the lore behind it is fairly original as well. I can definitely recommend getting the Up-Armored Deluxe Edition which includes not only the excellent soundtrack by Makeup and Vanity Set but also a 7 hour long audiobook that serves as a good introduction to the world and the three warring factions fighting over it.

I'm a simple guy, i like big i mean like real fucking BIG.

If we're talking Battletech then i've always liked mechs like Atlas, King Crab and Highlander the most but i do have a few smaller exceptions like the 80 ton Awesome and the Hunchback.

As for the setting, i like the Battletech universe but i also just like mech games like general, the bigger the better.

I like those little floating bastards in Empire Earth. You can get them with a variety of weapons and repair functions. Good stuff.

"giants-in-armour" is very descriptive yes :) Which makes the distinction between those two images quite clear, since the blue gender mech doesn't look like a giant in armour at all.
An evangelion isn't really a mech though, then again perhaps a 'biological mech' would be accurate for it.

Not at all, honestly. I just don't get the appeal. Maybe because I don't like anime in general, or anything even vaguely anime-ish. The closest I ever came to anjoying anything mech related was Robot Jox (more than Pacific Rim at least).

I'm definitely more of a fan of the comparitively slow and tactical mech commander series, but I'd still definitely want to give this a try.
And now I'm trying to think of banana republic countries/factions in a sci-fi setting... I suppose Dune might qualify :P Like most battletech fans I'd imagine I'm also a bigger fan of the 90-100 ton range, but while taking a strong likeing to a few of the smaller ones. In my case, the 55 ton bushwacker
http://cfw.sarna.net/wiki/images/2/27/Bushwacker_battle.jpg?timestamp=20100214153925

deleted