Certainly opinions vary, but we did extensive research before we bought our fleet. We laid out a matrix of the traits we needed for the roads, weather, routes and riders, forced ranked them, and tested literally every bike available, many on road tests.
At the time 4 bikes came out on top: Suzuki V-Strom DL650 (first suggested by our own Chip), Honda TransAlp, BMW G650GS and Kawasaki KLR650. All could do the job. Today we'd add the new Yamaha XT660Z Tenere and KTM Adventure.
We chose the V-Strom because of it lower costs, low maintenance requirements, great ergos, parts availability and performance. They came out #1 in almost all categories. It has a suspension with really long dirt-bike travel that sucks up roads, has a bullet-proof reworked/recammed SV650 motor (65hp, the same as a stock Harley), is very low maintenance, easy to wrench, good parts availability and decent prices, has a long wheelbase for the highway, does not have overpowering brakes (but still effective) and just feels ergonomically "right." But if you're short and physically weak it may feel a little truck-like because they are long, larger, tall machines with a higher center of gravity. They will, surprisingly, carve out mountain curves surprisingly well.
Keep in mind ego, prestige and the "cool factor" were not in our matrix. We're more hardcore riders when on tour.
The roads here can be challenging with blind potholes, reverse camber, blind decreasing radius curves, changes in pavement types and heights, etc. No one bike is the best for all conditions. A sport bike might be best for mountains, a big displacement cruiser best for the autopista, a dirt bike might be best for off road, and a moto best for around city traffic. But the "dual sport" bikes listed above are the best single tool for ALL the varied conditions. We refer to our V-Stroms as the Swiss Army Knives of motorcycles: they do nothing the best, but do everything very well.
Riding here is not like riding where you came from. The rules are different and not understanding them puts a rider at risk.
You might want to read our article on riding in the Dominican Republic from our MotoCaribe blog:
Two Wheels in Paradise: How to Ride a Motorcycle in the Caribbean Better yet, take a tour and use it as an edumacation on riding here.
Now if image is important and you aren't going to ride the entire country like we do, a bike to consider...if you're a decent wrench...is the Ural Sidecar @WD (yes, two wheel drive). I LOVE those things!: