Say, I love Debian+mod_rails and run it on my laptop which is my development platform. Yet, I am deploying to a production server running Ubuntu+mod_rails.
Is it better in a long run if I install Ubuntu on my laptop or are the problems with deployment so miniscule I can go with whatever the hell I like on dev. machine?
Thanks.
The problems with deployment, especially between debian and ubuntu, are so miniscule you can go on without worrying about it.
However, I wouldn't do it myself, because when that miniscule problem occurs, it's really hard to find and resolve. At minimum make sure you have a staging setup that is exactly the same as the production server and perform testing on that if you don't or can't make your development machine match.
Deployment is always a hassle with rails, but I wouldn't worry about it. You just set it up once with capistrano and it's pain free from then on. I use windows for dev, and mac or linux on a virtual host for prod.
I think this is true for any programming language, but no you shouldn't have different OS's for DEV/TEST/PROD. 99.9% of the time you won't notice a difference or problems, but that very small percentage 0.1% of the time, you'll be pulling your hair out trying to figure out what is wrong.
You're increasing the likeliness of things going wrong while you transistion between development and production.
Which means that you're just going to get more stressed out.
Which path you choose is really up to you ;)