I'm trying to help a school move to 'Google Apps' but i have concern.
One of the features I need is to retrieve current user's email upon form submission..which is only available if i purchase 'Google Apps for Education'.
Another concern is that since they already have existing email accounts, wouldn't they be hesitant to use new email accounts created from 'Google Apps for Education'?
What are your experiences so far in helping clients or businesses with Google Apps?
If you are moving an organization over to Google Apps your will achieve the best results if they fully embrace the ecosystem, including migrating all their email accounts to Google Apps.
There should not be anything preventing users from keeping their existing email addresses, simply set up identical account names in Google Apps and adjust their DNS MX records to deliver mail to Google's servers once you are ready to go live.
You are correct that if you want to automatically obtain the account names of users submitting forms then you need to be on a paid Google Apps account. This also lets you use their own domain for their Google Accounts, hence the ability to keep the same email addresses. Attempting to move to the free consumer-level @gmail.com environment rather than a paid Google Apps environment is not advisable as you lose most of the functionality that makes Google Apps great for organisations.
In my experience, if the users are unhappy with their existing system and you can demonstrate the benefits of Google Apps to them (low costs, universal accessibility, and collaboration functionality) they will be enthusiastic about moving over. If they are not interested in the benefits Apps offers and do not embrace the change, then there will be conflict each step of the way as you attempt to have them embrace a new way of doing things.