I'm a college student who hasn't had much experience with either pieces of technology in a classroom setting, but I would choose the IWB. I have had more contact and experience with an IWB than a tablet and can see it being more useful. While the tablets have their many benefits, it is not a necessity. Some arguments presented against the IWBs deals with distractions of "being next" these are going to occur with the tablet as well, especially when teaching younger students. There are methods that have been mentioned earlier to deal with this distraction and they seem very beneficial. The IWBs also provide movement for the students. Being able to go up to the board and work out a problem is a small, but needed activity. While some argue that is make classroom management more difficult, having students idle in their seats for over 6 hours can also negatively affect classroom management. Many IWBs also allow for multiple students to work at one time, these may cost more, but the technology is out there. I see far more conventional uses from an IWB than a tablet, but that is merely my opinion. Many other commenters offered great points for the uses of tablets though!
I would want the IWB. I believe that IWB’s are one of the best resources for learning in a class. Having students working with the IWB allows for more collaboration and participation from the whole class. I also appreciate the size of an IWB compared to a tablet. While a tablet has students working on a small screen an IWB allows for a student to interact on a larger surface. When considering younger students I believe this is especially important because it allows for a different part of the brain to be used. IWBs have countless ways that they can be used and they do not have many of the limitations of tablets. I think the scaling of the board really makes a difference in the quality of interaction compared to a tablet, even if the tablet is being projected.