Small companies are not penalised when adopting the Cloud. If you have 5 users or 200 users, the price, per user is the same. This is around US$5 per mailbox per month. Both Google Apps and Microsoft Office 365 are around this price.
With many people using Gmail for their personal email it is an easy move to migrate your complete company to Google Apps. You can transfer your company domain so your email address is @yourdomain.com and not @gmail.com.
Google offer some great tools to help copy your existing emails in Outlook to your new secure Google Apps account. Even if you are using a Mac and use Mac Mail, there are tools available to migrate you fully to Google Apps in the Cloud.