Before I answer which stallion I like better, I'd really like to hear your "plan". Every breeding should have a game plan behind it - not just because you love your mare and think she'd produce the most awesome cuteness of a foal. I'm assuming you have a valid reason to breed, or you wouldn't be posting here, but you didn't share it... and that game plan can alter which stallion you'd choose.
What do YOU hope to get from this breeding? What is your plan for the foal, what points do you feel should be improved in your mare (and don't say "nothing"... EVERY horse has a weakness that could be improved conformationally - and neither of your photos of her are great critique shots). Be critical of the stallions too - what weak points to they have, make sure they don't mirror your mare.
Next up, what has she got going for her to make her broodmare worthy? Has she competed and done well? Is she registered? Even if you plan to keep the foal "forever and ever" it's a good idea to make sure your butt is covered if you ever should have to sell. It's never something we want to seriously consider when we plan to keep a horse forever, but things happen, and sometimes personalities really don't mesh - so keep it in mind, and make sure you're giving this foal the best chance to be "marketable", for the first 3-4 years of it's life the ONLY thing going for it will be the successes it's parents have had.
In the second photo it looks like she has something hinky going on with her knee - is that an old injury... or an optical illusion? In the first photo, I initially saw a pony who needs to lose weight (make sure that's gone before you breed her! There are increased risks to breeding an overweight horse), the second thing I immediately notice is I think she has a longish loin (so pick a stallion with a short, strong loin - regardless of what you want to do with the foal) - the photo isn't good, but I don't like how she stands behind in either photo, and I have to wonder if a totally straight shot would show us some weakness in the hindquarter.
I'm not crazy about her neck, but that would probably change a bit if I saw her less overweight. The crest on her is not doing her any favors in terms of being feminine... it actually makes her whole neck look short and thick. It's also making it looks like she has poor neck/chest, neck/shoulder attachments.
So... to sum it up, with these two photos I don't see any glaring faults that would make me say "don't ever breed that horse"... but I also don't see a lot recommending her as a broodmare either, and honestly, some of that information will need to come from you in placement of better photos.