I have no qualms with ZGC being the default. The low latency that it offers at near G1 speeds is a very good trade off (IMO).
I just have a problem with G1 because in my experience, the best place for it is fairly large heaps. Get something sub 2 or even 10G, especially if you have a few cores to offer, and the parallel and often even the serial collector will give G1 latency even on major collections with superior throughput and overhead.
Are you talking about G1 in JDK 25, JDK 26, or JDK 27? While G1 isn't changing quite as fast as ZGC, it changes quite a bit from release to release. I believe that G1 has been made the default even for small machines in JDK 27 because of some very recent changes that have made G1 more suitable in smaller environments.
I just have a problem with G1 because in my experience, the best place for it is fairly large heaps. Get something sub 2 or even 10G, especially if you have a few cores to offer, and the parallel and often even the serial collector will give G1 latency even on major collections with superior throughput and overhead.