trailers vs. panniers: what is your experience?

Okay so this thread began almost two years ago and I'll assume the OP has long since made their choice.  But I recently went through the same calculus (and I've done it both ways), so here are my thoughts:

• Trailers are easier to load: toss stuff in and close the lid (or dry bag). 
  • But that makes it potentially harder to keep your gear organized in the long haul, and you may find yourself rooting around in the corners and other places looking for that small item that invariably settles to the least convenient spot.  Panniers- especially those with several pockets- reduce this issue but give you more places to stash items, only to forget where you absent-mindedly tucked them later, when you want them.
  • With panniers you're well-advised to develop and then FASTIDIOUSLY AND RIGOROUSLY stick to a system of what belongs where.  The instant you put something in a place it doesn't "belong", you've lost it- at least temporarily.
  • Using a trailer does mean you may have more capacity for larger / bulkier items than you would with panniers.
     
• You can't jackknife panniers. Jackknifing a trailer, especially on a high speed descent, may be disastrous.
   
• Trailers add complexity:
  • They introduce additional wheel sizes so you need to be prepared with the proper size tires and tubes; in an emergency you may get by with what can be gotten from the kid's bike section of a big box department store.
  • They lengthen your bike, making it more challenging to negotiate tight turns
  • If you're using a two-wheeled trailer you now have three separate wheel tracks to deal with- on unpaved (or poorly-paved) surfaces that may be a liability
     
• Trailers, even the lightest of them, generally weigh more than panniers so you are starting with a greater tare weight and reducing the payload weight accordingly.  In the end, this was the deciding factor for me, in favor of panniers. 
  • My trailer weighs 20 pounds empty, my panniers weigh eight pounds. 
  • That's 12 pounds of dead weight that I can eliminate without any reduction in available gear, or I can "spend" some or all those eight pounds to carry a few non-essential extras that add creature comfort.
     
• Trailers MAY be more weather-resistant than panniers.
   
• Both trailers and panniers add width to your rig; exercise caution when negotiating partial barriers or getting close to curbs, guardrails, and the like.