I only know St. Bart's. I am not sure what you mean by "Stuck Up." If you mean upscale then definitely. It is very pretty with lots of beautiful beaches, fancy shopping, bars and restaurants. I thought the people we dealt with there were very nice - spoke English and French and patiently let me practice my French!

The most fun thing was looking for movie stars - apparently a lot of them go there. We only saw one famous person, Tyra Banks, but it was off season so if you go on season you probably see more (I liked that aspect of St. Bart's.)

The port area is beautiful!

Yes, the two islands are different like night and day, and it really depends on what interests you as to which one to pick.

Saba: Very hilly, taxi tour would be nice, no beach, great hiking on Mt. Scenery, friendly people, eco-tourism, not much shopping, fabulous diving, very unique from other Caribbean islands. Scenery is great due to altitude, airport landing is quite a treat, and the foliage is very thick and lush like a rainforest. It always reminds me of being in a Hansel and Gretel village due to the quaint cottages everywhere.

St. Barth: Very upscale, much more modern than Saba, great beaches, good shopping, very expensive, great restaurants, some watersports, good "people watching" opportunities. Very tropical as in typical Caribbean scenery. Much more Euorpean atmosphere than Saba (or St. Maarten for that matter) Did I mention very expensive....ha!

Be sure to check out Shoal Bay on Anguilla. Beach like talcum powder; calm, crystal water like a bath....it's beautiful.

I'd be glad to help, if I can, with any other questions you might have.

We were two weeks in SXM beginning of Feb and did an overnight excursion to Saba. We fell in love with that little island so I must vote for Saba, especially if you want to try something completely different.
My husband arranged our 'excursion' with Sea Saba for the specific purpose of scuba diving. We flew over (in itself, an experience you won't forget) and stayed at Juliana's which included breakfast at Tropics Cafe next door (the view from here while enjoying breakfast, another experience I won't forget). As I don't dive, there was much concern on my husband's part as to how I would amuse myself while he was off diving the two mornings we were there. This turned out to not be a problem as our two days there barely gave me enough time to explore Windwardside, shop for lace, Saba Spice, and one of Edith's watercolour prints of Saba, and meet and chat with the friendly Windwardsidians. Previous posters had advised that dinner at Brigadoon's was a must but unfortunately it was their night to close - we ate at YIIK and still enjoyed a wonderful dinner.
If you want something different (how many beaches can you see) go to Saba for the day.