I've seen a couple of possible minor incompatibilities.
1. Regarding the "send a message from one of your disposable addresses" feature and the Opera 8.01 browser. This is FYI if you're interested; this is not a complaint!
The supplied link looks like this:
+word+username+5788qwer0j.recipient#dom ... ourmet.com
Clicking the link opens my email client, PocoMail, with the fragment +word+username+5788qwer0j.recipient in To and domain.net@spamgourmet.com in Subject. Right-clicking the link and selecting "Copy link address" cuts off the address before the # symbol, giving you this: +word+username+5788qwer0j.recipient.
2. I've never had a reply reach its destination. In replies, the supplied To header looks like this:
To: "text phrase" <complicatedaddress@domain.com>
For some reason, PocoMail always strips quotation marks from To headers before sending. Does this bother spamgourmet, I wonder?