Re: which trailer is better
You should also consider the weight rating of the trailers. The single axle trailer probably has a maximum axle capacity of 3500 pounds (boat and trailer weight combined). If the trailer weighs about 600 pounds, you can carry 2900 pounds of load at most. I'd guess your boat weighs more than that with motor, fuel and gear added in.
If it's a 2500 pound axle the load weight will need to be less than 1900 pounds.