I paddle with several women of different sizes and shapes. I think a good fit on a PFD is particularly challenging for women. Within our group of paddlers, we have Kokotats, Stohlquists, Lotus, and MTIs. And some of us have more than one, because the woman-specific models keep getting better. The strongest recommendation I can make is to find a paddling retailer with a variety of brands and several models specifically for women, and try them on. Ones I thought I would like best, I didn't. Ones I didn't think I would like so well, I did. If your friend gets a chance to try before buying, make sure she doesn't just put the PFD on, but also sits in a kayak, or at least on the floor with her legs outstretched, swinging her arms a bit as though she were paddling.

The PFDs recommended in this thread are all good. Also consider the Kokotat MisFit and any other models you find made for women.

But if its not possible to try before you buy, one of the first ones I would look at for someone 5' and 98lbs is the Stohlquist Bettie. Below, I've pasted in a pic of one from Stohlquist's site. One of the shorter more petite paddlers in our group has one (it's her third PFD). When that one came onto the market, she tried it and the fit was much better for her. The Bettie has a lower, more V-shape cut on the neck than most PFDs, which seemed to improve the "ride up" problem for her shorter upper torso.

Good luck. If you have any questions I can answer or ask of my six other women-paddler friends, fire away.

: I'm about 16 hours away from having built my first kayak. It is a 16'
: Merganzer and is for my wife. I'm looking for suggestions for a
: comfortable PDF for her. She is 5 ft. and 98 lbs. Any suggestions? Thank
: you!