One of the wags on here likes to say that guns are like noses - everyone should pick their own. Good advice couched in that humor, and forgive the plagiary with the knowledge that imitation is the sincerest flattery. I imagine you want to surprise her with her anniversary gift, but consider taking her with you to shop. If you are a regular at the gun shop, maybe they'll let you take one home to gift wrap with the agreement that you can bring her back down the next day and show her her other choices.
If your wife's hands are smaller than yours, as most women's are, she might find less of a difference between grips on the subcompact and the compact, and then she might think the smaller size is a benefit in carrying, concealing, etc.
My wife and both my college-age daughters really enjoy shooting my G26, for example. All of them are pretty accurate with it, and my youngest daughter can shoot the eyelash off a humming bird with it. (Not pushing Glocks over your choices - it's just what I have, and both of your choices are highly regarded pistols and either should be fine if the fit is right.)