personally i hold the pick like you do, at least i think.
if we call the nuckle closest to the hand the first nuckle/joint closest to the hand the first joint. and the joint that is closest to the fingertip the 3rd joint.
ok then so i have the first joint straight, eg parallel to the back of my hand, the second joint is at 90 degrees and the third joint is at 90 degrees. the pick lies agaist the side of the last digit, and my thumb is placed over it.
i prefer this way of picking, it allows me to do pintch harmonics easily as i dont have to change how i hold the pick. because there is a lot of surface area to hold the pick you can hold it quite loosly and have it not fall out your hand, as well as tightly. this allows a variety of tones. i feel it is more stable as the pick is almost in line with the wrist. i also feel it is good as it allows me to mute the strings above the ones i am playing (eg the low ones) with the plam of my hand as it is at the same level as the pick. lastly i find i can hybrid pick more easily this way (use the second and third finger like you would in finger picking) easier this way, and i find it is easier to switch to tapping with your second finger.
i used to hold the pick between fingertips and thumb, but i changed as i find the above method better for me. this does not mean it is better for you though.
i would advise you give his method a try see how it is and see if you think it is the best way for you. personally i would do it the way i described above, but you might be different to me.
hope this helps