Sea Tow just has "one service level" for the average boater...their philosophy is that it keeps thing simple for the customer...no worrying about if it's in "your" policy or not.
If you are worried about saving a few dollars or have different needs...the BoatUS different levels of service can be useful/a tad cheaper.
Yellow is more visible than red in dim light..and Sea Tow has instituted reflective tape in the middle of their stripes.
It really boils down to...if you boat in a small area...the local tower you select should be based on how well they do/can serve you. Who has more capt's, boats, equipment? Is it in better shape? Can you get to know them so they do the little "extras" for you? etc...etc...
If you are a cruiser...you never know who might give better service...as a whole the companies are usually neck and neck (and I know a boatload of both)...so look to the areas you most likely cruise and see who has more "homeports". Even then...some franchise owners will say there is a "homeport"...OK there is a boat and trailer nearby...but rounding up a captain off hours, etc might be an issue.
Cruisers are at the mercy of where they break down/go aground I guess....