Bellower.

Depends on if you use bellower elsewhere.  I got bellower in my first week and he was the second I got to 60 and gave masteries to.  Since it was my first account and I was very early on, I wasn't sure what to do and decided I didn't have the gear to do a 6 second farmer for a while so I gave Bellower stun masteries.  When I gave up on the arena (before they gave up on their fix), I took Saurus to 6 stars and got his masteries down to Cycle of Violence.  I don't even have "good enough" stats and he works perfectly for me.  If he gets his reset, he's 6 seconds (if you selected "unlimited" frame rate in plarium play, he was 7 seconds before I did that).  If he doesn't, he's 8-12 seconds depending on how many he kills in the 3rd wave with his A1 and if the food dies.  Prior to getting to gold 4, I failed about 1 time in 250 but that is entirely due to my gear not being good enough which I'll remedy at some point although I haven't failed since I got to gold 4 with the bonus upgrade.  

I have no great hall development to speak of, so these numbers are just from gear and level/ascension:

106% crit

197% crit damage

4115 attack

107 speed

[Edited to add - I had him at 101 crit rate because I geared him before getting a few masteries like a n00b]

Getting him in the campaign was probably the best decision that I've made and it really made me wonder why I hadn't done it sooner.

i find RAE to be an excellent farmer get her if you can

Hello Riptide, 

Definitly go with Bellower, he got way better base stats in General. 

Alpha H 

Yea, if you have bellower there's no reason to choose Saurus over him. 

Choose  Bellower  so  you  don't  have  to  see  the  "No  Aura  Skill  Selected"  message  all  the  time  lol.