The Legion Spawning Vessel is pretty solid in MKII. I don't use it in every list, but if you're playing more infantry heavy it trundles along behind pumping out lesser beasts and tilting the attrition game in your favour. I have found that it's something you always take the maximum unit for. The minimum unit suffers becuase it is both slower and has a smaller range, two issues that compound with each other to make it not really work. The only other downside is painting seven models and only getting three points out of it.