There should be a sticky, but there isn't.

Google "trailer site:bikeforums.net". Substitute "Bob Yak" for trailer, also "Burley Nomad" for trailer. You'll get 10^6 results.

These two account for >80% of the trailers you'll see out on the road. Pick the Yak if you need a trailer for singletrack (that's what it was designed for). Pick the Nomad if you want to use it for grocery hauling in addition to touring duty.

Either can be sold for more than half of original price after tour on ebay.

The Yak weighs 13.5 lbs for trailer, plus another 4.5 lbs for the yellow bag (yak sak), total weight is 18 lbs. The bag holds about 4,000 cu in / 65L closed. You can stack stuff on top too. 70 lb load rating.

The Nomad weighs 14.8 lbs total. Interior volume is 105L. The Nomad is lighter than the Yak, but holds more volume and carries more weight. There's an optional rack that allows you to carry more junk outside. 100 lb load rating.

The Nomad has a wider profile, so it's hard/impossible to drag it down singletrack paths. On the road, the wider profile and left-biased tow arm makes you more visible to traffic, and forces passing vehicles to give you a wider berth when passing - a nice passive safety feature.