Nirvana's Chrystal VS Green House's The Church

Hey, I was wondering if an experienced grower could help me out with somthing. I was looking at chrystal on the tude, and the church and they seems to be almost equal. I was wondering if anyone could let me know which may be easier to grow, yield, and which may be a little more potent? If there is somthing a little better i could use suggestions on what to look at or where to find. Please someone help me out im stuck.

I noticed on june 4th- 7th tude is having a nice 5 seed give away with purchase of over 20, Question i have is i havent bought anything from the tude so i havent been to their site alot Do they do this EVERY month or is this a special thing, Also besides the 5 seeds do they still give the "UFO's" with purchase or only the 5 seeds?

Nirvana Chrystal ... two pheno , very regular weed ... 4/10

Thanks for the advice. I ended up buying Green House Big Bang instead of either. A few other have said great things about them so i figure i'll give them a try.