There really isn't any single "better" option. Amadeus ALTEA is shiny and new with all sorts of bells and whistles, but it comes at a serious cost and is very resource intensive. SABRE has improved their product offering in recent years and is cheaper than Amadeus (and a much shorter waiting list for implementation) and is quite popular with growing airlines seeking expanded interline functionality. SITA PTS is probably the cheapest of the lot and has more basic functionality, but it is a very hardy and stable system which operates better than the others on unstable and slow connections.