The Iron Grumblers arrived from Ramshackle a few weeks after ordering. They take some time to arrive because the company doesn't hold stock, instead casting as orders come in.
Price; the 3 tanks came to £27 including postage. This compares well to the GW equivalent, with unpainted Rhinos going on ebay for about £15 -£20.
Size; to Space Marine Rhino; about half an inch longer and taller, so no complaints from opponents.
Modular; I like that all the bits come separate, so there is some room for customisation and adjusting the height of the central parts.
Material: Resin, haven't used it before, probably won't buy anything so large in resin again. It's heavy, but feels fragile; if this gets dropped it's going to shatter like peanut brittle. The little protruding exhaust pipes might not survive much transportation.
Casting errors: The tank tread detail is significantly obscured by faults. All I could do with them was chip away the biggest lumps and think about hiding all the gouged out holes with mud or something.
Bits; no bits, unlike GW kits. How much of an issue this is depends on your own access to bits.
The difference in price helps me see past the models' faults, and I'm looking forward to filling them with cultists and marines.