Anyone whom runs their own domain can configure SPF as they like, and/or choose to implement DMARC.
We do exactly that, our mail server supports several domains in which has its own MX and SPF Records which woks great and haven't had any issue since we have put the SPF in place.
They seem to work in improving the mails delivered successfully stats . Anyone whom sends emails to the big USA ISPs will find they need both or the mail is blackholed
SPF will be fine for those big USA ISP's, DMARC is just a feature that combines both DKIM and SPF, so all DMARC does is check what the sending server is using and will use that.
So as long as you have SPF and/or DKIM installed you should be fine.
And we already know that SPF is there so that the receiving end know that the server that sent the email is allowed to send emails for that domain, DKIM is just there to stop tampering of the actual email, so you can tell it to protect the FROM, TO, DATE, SUBJECT, MESSAGE-ID etc, granted this also needs to have a RSA Public Key stored in each of the domains DNS records for this to work.
So by using both SPF and DKIM you are protecting your emails from tampering and also making sure they came from the correct legit mail server.
Now do I think everyone should install DMARC, if your doing a fresh install of your server that consists of a mail server with one or more domains with their own MX Record, then yes, if not then just install SPF and / or DKIM.