I suppose it depends on what sort of benefit you might be looking for...
in terms of getting detailed information about specific outfitters, or discounts on hunts, or anything else.. theres really no tangible benefit that I am aware of that would come from joining either organization..
but.. if youre interested in participating in the preservation of wildlife, animal and habitat conservation, etc.. both organizations bring quite a bit to the table..
mere membership alone "helps"... a % of membership dollars go towards various programs, etc..
but DSC and SCI are organizations in my experience that you get out of them in parallel with what you put into them..
Ive poured a significant amount of time into DSC for example.. I have volunteered/worked at the last 6 shows... through volunteering I have gotten to know several outfitters, as well as several other members.. both of which have provided a wealth of information and additional contacts related to international hunting..
my wife and I are life members and used to attend the monthly meetings in Dallas (pre-COVID, which shut them down at the time) routinely.. through the monthly meetings, we met several other members, once again deepened the rolodex with contacts of like minded people with similar values, made several friends, and got involved in a number of different activities that the organization puts on every year (everything from New Years Eve parties to Big Bore Shoots to training events, etc)...
There are also opportunities to serve at the local chapter and at the national level for those that are interested across a wide variety of programs/projects... anything from legal efforts to research, to youth education, to volunteer leadership, etc.. etc..etc..
While I think most would tell you that historically (recent history at least) DSC's annual convention is preferred (while both do an incredible job with their annual shows).. but most prefer SCI's more aggressive lobby/legal office and willingness to be proactive about hunters rights, and other issues..
Both are (IMO) good organizations that do a lot for hunters around the globe and worth the relatively minor amount of dollars required to maintain membership..