Hmm...
Well, it's hard for me to decide which one I like best.
They are all good in my opinion, but, I think it would've been better to make Entei ground type, so the dogs have their strengths and weaknesses.
Raikou(electric) can defeat Suicune. Suicune(water) can defeat Entei. Entei(fire) can possibly beat Raikou with a strong move, except, it won't be "super" effective, unless he new earthquake.
This is what would happen if Entei was ground type.
Raikou(electric) can defeat Suicune. Suicune(water) can defeat Entei. Entei(ground) can defeat Raikou.
It would make it more of a challenge for Raikou, it would be more interesting, and, there's not much ground type Legendaries! :P
The only ground type legendaries would be Groudon and Arceus(Arceus, if holding earth plate).
And thats my opinion.