UCD Honors vs UCSB Honors vs UCSD

I’ve been offered admission into the honors programs for both Davis and Santa Barbara but I’m not sure what the differences are between them. From what i’ve read on their websites, both of them offer similar smaller benefits (priority registration, upgraded library usage…). Davis offers more research projects/ opportunities, as well as seeming more selective. Meanwhile Santa Barbara seems to try and guarantee those things without the honors program. Could anybody shed some light on the topic?
Additionally, how does UCSD without the honors program compare to the others with it? I’m a Biology major so I’ve heard San Diego is much more competitive which could hurt my chances for research and other opportunities.