I have had tons of fun playing the
IA dread mob list. My suggestion is take as many vehicles with blast weapons to compensate for Orks' poor
bs. I have had particular luck with the big lobba on a big trakk. The big winner, however, is without a doubt the mighty grot tank. These little buggers are points efficient and surprisingly durable with their 5+ invulnerable save (plus they are NOT open topped, so they are resilient to most light arms). I use a squad of 6 with 4 big shootas (2 on the tank commander) and 3 grotzookas. The big shootas enable them to fire at range and more than 6 blast templates is generally overkill given the limited range of the grotzooka. I stay away from rokkits, since there are other platforms for them.
The biggest issue with the list, though, is that it is quite outdated. I use the mob rule (which penalizes the army) and all updated points/rules for units in both the
IA list and the new codex. I have a discussion with my opponents first.
The army is always tons of fun and fairly competitive. I run almost all vehicles and walkers, so the opponents has to choose between the long range shooting power of the list (which is surprisingly significant, although dependent on decent rolls) and the advancing, clanking might of the walkers. Allying it with a standard Ork codex is very useful in order to gain mek guns for even stronger fire support as your wall of metal advances.
Automatically Appended Next Post: Oh, and the grot mega tank has served me well. I give it all big shootas and a pintle mounted shoota (just for

). I keep it at range just to add a gak ton of
bs 4,
str 5 shots. It is a fairly cheap price tag (points wise) and usually makes up its investment.