If you haven't already achieved everything you wanted in regular mode, I don't suggest ironman.
Ironman was made as an extra challenge put in for those that either find regular mode too easy, or have already accomplished whatever goal they have (ex: 99 every skill).
There are no "benefits" to ironman, other than having a special icon by your name in chat and being on the ironman high score chart in addition to the regular high score chart. On the contrary - ironman is harder. Ultimate ironman is much harder.
I play ironman because i've already gotten all 99's before on multiple servers. I still have desire to play, so this extra challenge at least mixes it up for me. A lot of skills are too easy in normal mode, like herblaw when you can have 8 accounts all gathering the materials for your main. Ironman forces you to gather everything yourself. You also can't just buy your levels like smithing and prayer since you can't trade or use the auction house.
Vet Paul
Iron Paul
Paul
[img]http://i.imgur.com/or9jdo2.png[/img]