Flown with globespan Glasgow to Orlando Sanford a couple of times - Economy and Premium Economy. All I can say is, it's cheap, no frills. Was quite a culture shock, I had previously flown BA over the Atlantic and was used to excellent service, individual TV, blanket and pillow, free drinks etc.
Their service is not bad, it certainly isn't RyanAir, but if you fly economy you'll be buying your own earphones, meals, drinks etc, and you'll have a very cramped seat (although, the planes they fly over the atlantic have just 2 seats at each window side, and 3 in the middle). If you pay the extra for "Premium Economy" you get very little extra - a few inches extra legroom, free earphones, meal (I took the veggie option when I flew Premium, was passable), pillow and blanket (didn't realise how much I missed them until I flew economy!). Don't expect to be entertained while flying either, Economy and Premium classes each just have basically a projector that plays the movies onto the bulkhead up the front of each cabin area. If you're sitting at the back, or to the side, you're not going to see anything. Thankfully, I didn't really want to see "My Super Ex-Girlfriend" anyway.
So, Globespan because it's very cheap, and for no other reason!