Microsoft claim CE to be real-time. As to how 'real time' it is and whether their real time matches your requirements for 'real time' is another matter. I can say that with my recent experience in doing a data logger on a HP Ipaq 2210 CE machine, I did have some real time issues with comms and that was solved by playing around with the task priorities. So, I was fairly impressed. As to whether I would choose CE over anything else would depend on the exact application - if there was GUI involved, CE may be a good choice. In the above instance, I really had no choice in O/S, but the experience was positive - the free tools are pretty good along with the simulators. The one thing that gave me the most grief was converting UNICODE strings to ascii strings - that took a bit of searching on the web. CE uses unicode internally and I wanted to log data in normal ascii strings, so I did everything in unicode and converted to ascii when I wrote the file. I can't remember the exact naming off the top of my head but there is a macro that does the conversion, but it allocates memory for the destination string. since my code was in a thread, after a number of string conversions, the application would abort. The solution was to do the string conversion in a subroutine and a declaration in the subroutine would tell it to clean up the allocated memory.