Using a direct global route announcement using BGP has also some drawbacks, especially regarding costs.
1.) A BGP enabled subnet in most of the countries is astronomically costly, being regarded as a "professional" network approach by the ISPs
I would suggest going for a small ISP in a datacenter, and not a colt or verizon or level3 or cogent or ... Just take a very local ISP, who still has good peerings and stuff.
The ISP that we got to start with our 44.144/16 BGP announcements is a very small ISP consisting of 3 people, and the owner is also the main network engineer. He thought of this as a challenge and was excited to be doing this. Furthermore we are lucky enough to get about 100mbit of bandwith for free from this ISP as a sort of sponsoring to the hamradio community in belgium. This means that the ISP is small but is still doing enough traffic that they can give away 100mbit without making any losses.
2.) You most likely need a router capable of processing a full internet BGP table, which is HUGE, comprising more than 48k prefixes reaching a size of over 10MB. This needs filtering, big memory resources and fast CPUs. Raspberies won't do the job here.
We use a Mikrotik CCR1036-12G for this. Cost is about EURO 800 (sounds like much, but hey, a decent VHF mobile radio costs about the same)
3.) You will still have to provide tunnels in order to reach and be reached by 44net islands not using BGP.
This is correct, we still route 44.0.0.0/8 to a system that does IPIP to the rest of amprnet. However, the route from the rest of amprnet back to us could be done purely over the internet. So the question might be, do we still need to announce ourselves in the encap file ?
Correctly setting up a stateful tunneled system or a BGP enabled network is certainly more complicated than a P2MP IPIP tunneling system.
Depends on experience I guess :)
73 Robbie, ON4SAX