In recent memory i can recall having Magnum (ex Frankfurt) and Haagen Daaz (ex Hong Kong) ice-creams.
In terms of service quality, i have never had to make any complaints about the level of service. The most endearing thing about flying on SQ is hearing the work chatter between the stewards/stewardesses in Chinese/Singlish. Sometimes I wonder if the professionalism is diminished a bit when they code switch over to Singlish and is overheard by non-Singaporean passengers, but it is a bit heartwarming to hear Singlish after a tiring work trip or long holiday where you are a bit homesick.
Handling a lot of Y passengers can sometimes mean some lapses in service, but most lapses are trivial, and we shouldnt forget the crew is human. On a recent 12 hour Frankfurt-SG flight, i noticed a passenger did not get his preferred meal choice for his first meal as it had ran out, and a stewardess assured him that he will get his choice for the second meal (breakfast). This shows SQ still emphasise on the little touches to make a flight journey bearable and memorable.