I think it is crucial to have data from several years to see whether a coin is secure or not. We can say with certainty that Bitcoin has been attacked often times but never failed. I don't know IDENA but can it be said that it is as secure as Bitcoin?
Saying "secured" i ment that it is hard to attack it using 51%, hard to be manipulated by single entity that owns majority of voting power. Not the code.
Idena is surely not as secured as Bitcoin but its low cap shitcoin. We are talking here about green coins (low carbon footprint) not "digital gold" coins (reliable, secured, huge). Idena is interesting because its not POW (the more power you eat the bigger is your vote) or POS (the more money you have the stronger is your vote) its POP (1 person 1 vote, equal voting power - achieved by Touring test. Every miner can mine with old laptop or 5$ vps or even for free delegating voting power to friend/family member).