I have a good deal of exp. with a lot of shanti's gear as well as rezdogs. The black widow is a very stable and uniform strain that does not have the variation that you will get from the sour diesel "IBL"......With all due respect to rez, the only issue I have with his "ibl" is the amount of variation you get. An IBL should not have the amount of variation that his Chem and Sour "IBL's" have.
As far as potency I would raise the hand of shanti's before Rez's. Although both breeders are very respected in that aspect.
Flavor--Taste That is subjective and really up to you. Personally I have enjoyed many strains by both breeders.
So to say which strain is better to grow or stronger is kind of subjective to each grower and what they are looking for. Both breeders are known and respected. Both have great potency strains. However, Shanti's gear will be more uniform and will not have the variation.
In my general opinion...your wasting your $180ish dollars with rez's gear. Its nice stuff with good potency and flavor but its all if you can find the right pheno and there is alot of pheno's in all of his gear. His IBL's are a very big joke...especially if you ask shanti
If you do the research you can order straight from shanti and he is a great down to earth person to work with. If you do research on Rez...you will find out he is loved and hated by many and is a very arrogant sob....and he is probably proud of that. Shanti is a humanitarian and a very noble person...you cant go wrong with his gear.
If there is variations in some of shanti's strains its well known and documented on his website. Rezdog on the other hand is more like..."heres some $180ish seeds...there should be something good in there"