Ipsy is the only one I've used so I can't compare but I like it well enough. They lack consistency though - some months are great and some are pretty terrible.
I had Birchbox for six or seven months. I'm not a huge fan. It was ok, but every box contained a foundation or bb cream sample, and all of them were too dark. Several had food or tea as one of the items, and I wasn't interested in that. I don't think it's a bad idea, and if I had the extra money I might have kept it. I left feedback and filled out my profile, so I thought that they would at least stop sending the foundation samples, but they never did.
Birchbox has more skin care, lifestyle products, etc. than ipsy Glambag. The glambags are pretty much all makeup with a few hair products or skin care thrown in. Glambag is also much more inconsistent from month to month, some months are AWESOME and others are total garbage. I have been getting both since the spring and at the end of the year I plan to cancel Glambag.
If she likes nails, there is a box called Julep which is $20/month but gives you full size polishes every month and other items too like lotions and stuff. I don't subscribe but a lot of people seem to like it. I believe Julep lets you skip months which BB/Glambag do not let you do without canceling your subscription and re-signing up which can take weeks due to the wait list.
I've had birchbox and I have Ipsy now. Birchbox pros: i liked the perfume samples, and their makeup seemed a better fit to the things i like (colors, more eye shadow, mascara, lip gloss, less lip liner and blush), earn birchbox points by reviewing products on their website... you can use the points towards purchasing full size products Birchbox cons: hardly ever any full size products in their boxes
Ipsy pros: MANY full size products, i like that they give you the little make up bags, i use them for lots of stuff ipsy Cons: I've received make up that doesn't go with my skin tone, even though i have customized the box with my skin tone. Hot pink blush and dark navy eye shadow just don't work for me.