DW and I own a large number of farms and ranches in a really big state in the South. Our play isn't farming or commodities per se. Rather, we're looking at long-term development potential as the ultimate payoff as these properties are in the "path of growth" of a nearby big metro area, and we're willing and able to wait for this to happen (or not). So the farming aspect is really incidental. In the meantime, we've been able to monetize our holdings through a healthy and steady rental income from cattle grazing and crop growing. We've also looked into other forms of land exploitation such wind farming, mineral exploration, CRP, etc., with mixed success.
I think it depends on what your goal is with buying farmland. If your goal is simply one of diversification, REITs and ETFs are the way to go. Your investment $ will stretch a lot further and allow you to diversify your risk.
Direct ownership won't really make any sense for most people. It requires large capital commitment (mortgages for land investment are more expensive and harder to obtain); it requires a lot of research and local knowledge to pick the right propert(ies) (e.g. you don't want to buy a property next to a "non-operating" municipal landfill site); it can be a lot of work and expenses dealing with tenant leases, broken fences, leaking "ponds" (i.e. man-made lakes for irrigation) that need to be repaired, (re)filing ag exemptions, stock intrusions, illegal dumping, right of way/easement for utilities (e.g. negotiating for fair compensation if they want to run power poles over your land or laying utility pipes underground). All this stuff has happened to us.
If you're an absentee owner, to make everything run smoothly, you will need to build an extensive on-the-ground support network of local contractors, neighboring farmers/ranchers, contacts in local government agencies (especially those handling exemptions, property valuation, title research, etc. etc.), title companies/real estate agents. The cliché "everyone knows everyone" is absolutely true in small farming towns/communities. Once you're plugged into the network, you have intimate knowledge of the local land market, who sold what for how much, what properties are for sale, what properties to avoid, who to call to fix the broken fences/leaking ponds, who is looking to lease land for his cattle, etc. It took us a good dozen years to build up this network. It's a lot of work but it's been worth it, and we've actually made some great friends along the way.
IMO, unless you have a lot of capital at your disposal and are willing to put in the hard work to do the research and build up a network of local support, your best bet is going with an investment vehicle where you can pool your money with other investors.
Lucky Dude