I have to force myself back to working on the 4 from time to time to make certain I'm still grounded. The cool thing is, if you take the time to learn to play things on the 4 that you've previously only played on a 5, it makes you stretch. Can't explain it. You just have to try it.
But I am still primarily a 5 string kinda guy.
Now, for secular stuff, I do tend to work out more with a 4 because it just feels right.
Peace,
James