My perspective is from many years of riding mountain bikes on single track trails, and another thousand miles or so on an ebike in Daytona Beach Florida. In DB I ride a combination of pavement and on the beach.
People see a question about Florida and instantly go to the fat tire discussion. The only loose sand I ride on is about 30 feet from any entrance ramp to the beach to the harder packed sand. My ebike has Schwalbe Super Moto X tires, which are smooth and 2.4 inches wide. The do not handle well in the soft stuff, but who wants to ride in the soft sand anyhow? It flings sand into every nook and cranny of your bike, even with fenders. Meanwhile, when on the pavement the tires are extremely quiet and smooth rolling. Before this bike I would ride an old mountain bike in the same places - the smoother tires are preferred for most of the ride. The mountain bike tires were only 2.25" wide but had knobs on them - they handled soft sand better but vibrated more everywhere else. I cannot imagine needing 4" + widths.
Suspension is helpful because you cannot help but run into potholes or even divits on the beach. Front suspension on any $2000 ebike will be okay, but not great. But it should suffice. Seatpost suspension is nice (I have a Thudbuster LT) but can run $150-250 - quite a chunk out of a $2000 budget. The posts can be purchased aftermarket. Cheaper options around $50-80 should do a good job too.
Replacement handlebars or stem risers are cheap to buy and easy to replace - just make sure that there is enough length to the cables to raise the bars. This will allow you to sit more upright if it turns out that you don't sit as upright on the bike as you might have wanted.
In flat Florida any kind of brakes should suffice. Hydraulic discs are very nice but usually found on pricier bikes.
Get the longest fenders you can find. Sand comes off the back of the rear tire and may make it up to your back. It will also stick to the tire long enough to fall on the chain right behind the seatpost. It will also come off the front wheel right onto the chainring. Use a dry chain lube, not oil, and less sand should end up in your chain. I use Boeshield T-9. Goes on liquid then dries. Very little dirt builds up on the chain.
I like speed. You may not. Decide if you want a 20 mph bike or a 28 mph bike. Speed usually equals more money.
Take a look at what kind of sensors trigger the motor. Cadence versus torque makes a real difference in how the bike rides. My year old RIde1Up 700 cadence based bike doesn't really care how much I pedal, only that I do pedal. My newer Ride1Up Limited is torque sensor based and feels more like a real bike to me. It takes more effort on my part than the 700.
Bike brands that have looked good to me in past research (mostly based on value/$$ and features I liked) that should have bikes in your price range:
Ride1Up
Rize
Juiced
Mountains to Sea bikes (M2S Bikes)
Charge Bikes
A retailer that has a lot of good bikes is bikesdirect.com. Like everyone else, they are often on backorder. They use a lot of Shimano motors on their bikes, which you won't usually find in the $1500-2000 price range. Shimano is very high quality, and much better than the inexpensive Chinese stuff, but it won't go more than 20 mph whereas the Chinese stuff is not limited for top speed. Shimano will use torque sensors and pedal like a regular bike, only easier. I would consider this to be a better quality bike than the direct to consumer Chinese bikes listed above -
http://www.bikesdirect.com/products...cycles/ebikes-electric-bikes-elite-eurban.htm
Final note, these bikes all get heavy. I toss mine in the back of my truck occasionally, and its a chore. Think about whether you are ever going to transport them and how. Racks can get real expensive too.
Have fun researching.
