If you are going an IA8 list then the big traxx are a good option. However a costly one.
I just purchased a Mega Dread off of someone, new in bags and saved a crap load of cash.
When I was going to place an order I was going to get the Mega Dread with a klaw and a killkannon. I have heard a lot of people go for two claws but what is the point. With our limited options for taking ordinance and the fact that it is on a walker is even better.
I liked the mega dread better than the meka dread but that depends on ur list build and if you are going for Apocalypse... I wanna field a Dread Mob for a formation so there could be some use for taking a Meka Dread.
My vote is for a Mega dread with killkannon and klaw. Keep him near a KFF and you can put down a good barrage while advancing. That was my number 1 want from FW. I still am going to be ordering a big traxx though plus a kill kannon for it and a kannon for my big squiggoth. I also like the Boss on a bike but I have seen a few of them for sell locally so I should be able to save a few bucks.. Probably not as much as I did on the Mega Dread though
I got a steal on it and on my big squiggoth.