:lol: I was knowing it's like a 'debate topic' and people will have their different opinions on it. And all the opinions are valid in certain scenarios.
It's finally upto you ! What u'll do with it..... If you think you'll become lazy to study h/w and design s/w on ur own, after learning Arduino, then don't touch it.
But if you think
1. of doing reverse engineering on Arduino sample codes, various shields etc
2. of designing your own custom libraries, support for new peripherals
3. knowing some complex issues like RAM management, IAP etc and how they are are addressed in sample codes
4. to be sure to manipulate vast spectrum of sensors, protocols, interfaces etc for time being and think u'll further dig into it. (this removes fear of new tech n enables to follow reverse engg opt)
5. contributing to community work and learning many things from forums
Then definitely go for it ! As I said....... you will never regret ! ;-)
One more thing, when open s/w movement jst started, ppl was thinking it as some sort of craziness, then eventually they came to know that even 'toys' can do wonders !This enforced many big players to change their strategy and adopt new changes !
Open h/w moment is now catching gr8 momentum, and I am seeing many start-up companies going by this way(literally with complete Arduino based platforms). It's not long when even big players will adhere to it. (recently Broadcom released all its VideoCore driver codes to support Raspbrerry Pi community)
So, the point is, u'll never know what's going to happen, and how the industry will react by seeing 'Arduino' in your resume !