Here's more details on the Singapore Savings Bond: http://www.straitstimes.com/news/business/banking/story/singapore-savings-bonds-8-things-you-should-know-20150512
(1) Returns are 2 - 3%: Currently there are certain bank accounts which give around the same returns (eg: OCBC 360, UOB One account and DBS accumulator), and this is fairly liquid (although the SSB are not significantly illiquid)
(2) Cap is 100k: The drawback of those bank accounts are that the cap for interest are limited to the first 50k. If you have excess cash above 50k that is used as emergency cash and not for investment purposes, this could be a good place to dump to. [honestly though, i don't know who has 150k spare cash lying around - but there are many cash rich people that i don't know of]
(3) Capital guaranteed: Well almost. But backed by the government, that is as good as it can get. Relatively safe haven for your money.
Conclusion: Will i bite? I will potentially, if i have a lot of cash sitting around.