It's just a personal preference based on feel. I tried it for a little bit but I like the feel of grips better, more specifically just oval grips

Its all about feel, I personally use finger tips. They can help you to get more finger in the ball and give you more rotation, so if you want more then you could use them. Also, my best advice is...if you use them now...I wouldn't change. but its what is more comfortable to you.

No grips!

Tried no grips and it does assist in a cleaner release, but as spmcgivern mentioned, I started developing a callous and it was uncomfortable, on top of that, the feel was just not what I prefer, grips all the way.

At the end of the day, it's all about personal preference; The only true way to know which way either way is trial and error, and you judge accordingly.

Yeah trial and error is probably how I'm gonna judge.  Lord knows I have enough equipment to take my time. 

Thanks for all the replies fellas.   

Maybe pro shop guys can input more but I don't see why you wouldn't be able to get a ball drilled without grips and if you don't like it, bring it in and have the your driller make the holes bigger for grips. Maybe they can't, I dunno, but I can't imagine that being an issue

When I was younger, grips used to tear my fingers up when I would rent lanes by the hour and throw game after game.  Since I picked up bowling again I ended up drilling all my balls without them but have one ball from back in the day with them.  Still torn if it was mistake considering my body can't take throwing enough games to mess up my fingers these days.  Oh well guess as the poster above says if I find it really is a problem I can get grips added.