Here is a couple of pics for comparison. Overall size will be close where the 6906 will have a fatter grip but the 4516 will feel longer and narrow. Width of the frame, measured just under the beaver tail is 1.00 on the 6906 and .790" on the 4516. Slide width is .925" on the 6906 and .985 on the 4516, this does not include the safety. All of the 3rd gen compacts are reasonably close in size. excluding the CS models.
My 4516-1 is the US Marshals Edition
If you like the compacts, you will like anyone of these: 4513TSW, 4516-1, 4013TSW, 6906, and 3913