The item is certainly not bad... It really just depends on what you want out of your item slot. I mean obviously we're talking about health and armor items so our options are Sunfire, Deadman's and Randuin's.
Randuin's is easily the best one of the 3 for pure tank as it's +10 armor outweighs it's -50 health in addition to reducing Crit damage and AS. It also provides a nice AOE slow if you need extra sticking power.
Deadman's provides a really nice MS buff (which is the main reason why it is more popular than Sunfire imo) in addition to some bonus single target damage and slow on impact.
Sunfire is the most offensive of the 3 easily out damaging Deadman's initial hit after a few seconds but provides no mobility nor CC.