Mailah of Gmail vs. Yahoo is no picture ads, but if you use a program such as Outlook, it makes no difference.
I know people who had to switch IP provided email addresses when they switched providers, so, unless there’s some law which they (and I) don’t know about allowing one to keep his email address regardless, I wouldn’t recommend it.
Switching active email accounts shouldn’t be too difficult; just have all mail forwarded to the new address. (Unlike the USPS, there’s no six month limit.)
All the real techies out there can correct whatever mistakes I made in this post.