Not that I think that SPF is the ultimate solution (it is merely a thin layer of lipstick on the pig) but I don't agree with many of the assertion of your "spf is harmful" link.
- pre-delivery forwarding servers just need to be added to spf. If you use random third party smtp relays, then this is precisely what spf is trying to avoid.
- the way internal servers implement aliases is their problem, there is not necessarily a need to go through an smtp relay (my mail server doesn't)
- failover mail servers should check spf on incoming email and then have a trusted relationship with the primary server so that spf isn't enforced when the failover delivers to the primary (that's the way my mail server works)
- spf uses DNS. So what?
- ISP lock-in. If you control the domain/DNS entries, there is no lock in. If you don't, then you are already locked in anyway.
- doesn't allow dynamic IPs. I'd argue that 1) it is a good thing 2) it's not really the case, you can specify a domain in spf, and this domain can be a dyndns style domain with a short lived TTL resolving to your current dynamic ip. And in theory you could also dynamically update your spf as your ip changes with a short TTL (like a dyndns-style entry).
[edit] and actually what is going to kill you with a dynamic IP is not so much spf than the fact that the reverse dns of that IP won't resolve to your domain which is a big spam red flag for most smtp servers.
