Raspberry Pi or Arduino?

Raspberry Pi and Arduino are two different animals.   The RasPi runs Linux where the typical Arduino board does not, expect for something like a Yun or Yun 2.  Actually you can run the Arduino IDE on a RasPi meaning your could have a RasPi as a Linux host to program an Arduino board. 

With regards to which is appropriate for a school, that depends on what you mean by school.  What grade level are you talking about?   I know kids today are quite bright, but I would not expect a 1st grader to be coding a Linux board such as a RasPi; LEGO.Mindstorms perhaps.  An Arduino with some sore of,  gasp,  Blocky IDE or Code:Blocks might be more appropriate.  Older kids such as in Middle School or High School might be better served with a Raspberry Pi running ROS.

I suppose the short answer is, it depends. 

Agreed, my choice would have been the Pi but the lack of analog inputs would make it more difficult to teach the basics in a classroom environment.

Again, it depends on the application. My current project is better geared towards the Arduino, the next one? Who knows.

They're all cheap enough to have at least one of each imho.

I like both, but raspberry pi is great for schools; its affordable, and it teaches simple programming!

I started 2 and half years ago with Raspberry Pi model B and i think this is a great tool for learning everything about the Linux platform.

U can install various images, Raspbian, Kali linux, XBMC etc and actually i learned to configure and to setup a linux pc from the Raspberry Pi. It is better than a virtual machine with Linux, you can do whatever you want and then reinstall a same or a different distro, without warring destroy your hardware.

Six months now i entered the Arduino world and after an entry level kit with an UNO, now i bought a small Actobitty 2 wheels robot and a Leonardo.

Arduinos for me are very handy controlling motors, leds and every other machine that can be hacked.

I vote for Arduino but with a special love for the Raspberry PI.

I'd go with ODROID-C1, which costs the same US$35 as RasPi B+ or RasPi 2.  It's approx 50% faster than RasPi 2 and has analog inputs, something missing from RasPi.  ODROID-C1 has a dedicated 10/100/1G Ethernet port and faster SD card or eMMC for even more speed.  I use mine with a USB hard disk drive as its root file system.

mconners has some excellent 'blogs on the C1:

http://www.element14.com/community/community/designcenter/single-board-computers/blog/2014/12/23/odroid--oh-boy

http://www.element14.com/community/community/designcenter/single-board-computers/blog/2014/12/23/adc-on-the-odroid

This really depends on the project. I may need good programming on board and internet access go with Pi. If I need time critical hardware interfacing, Arduino is best... And then there should be a third choice that blends the two IMHO.

Clem