I have stayed at the Dan three times. The first two visits were amazing, perhaps some of the best hotel stays in my life. This last one was pretty mediocre. I have heard that the Sheraton Tel Aviv is on the shabbier side, so I plan to try the Hilton next time. I'd rather stay on the beach side, so I'm not so keen to try the Intercontinental.
Although Tel Aviv is great at any time of the year, I think it would be more fun during a warmer season than winter.