Both are excellent and a great deal for the money. I would tend to choose based on their coverage in my specific cruising areas. We cruise a lot of areas so have both.
Seatow has the Eastern US blanketed. Somewhat less in the Gulf, west coast only for the San Diego and LA areas and no Great Lake coverage. Seatow does provide some coverage (up to $225 per hour and a total of $5000) when out of your home area.
TowBoat US/Vessel Assist does provide Great Lakes service and west coast service including San Francisco and the PNW.
Note that neither includes any form of salvage as that must be covered by your boat insurance.
Plans:
Seatow's Gold Card is $169 and offers all coverages you would expect. It covers any boat you own or that you charter, lease, rent or borrow. It does include dock to dock tows and the Universal coverage up to $5000. They do offer Corporate (same price) which is required if the boat is in a Corporation or LLC name and only covers that boat. And they offer a service for commercial boats which requires in addition to the $169 per year a fee of $100 per hour. Last they offer for $365 a professional mariner card for those making their living on multiple boats they don't own and it covers any boat they operate. It is primarily used by Captains.
TowBoat US has a gimmick plan you need to be very wary of. Many marinas are including this as a freebie or dealerships give it to you. It is the Basic Plan and costs $24 per year but it only pays the first $50 of any tow charge. I find it pretty bad that they offer it and people are led to believe they have something of value. Obviously it's an attempt to then up sell. They then have an Unlimited Salt Water at $149 and Unlimited Gold at $181. The only difference in those two plans is that the $149 plan pays only 50% of home dock tows and the $181 plan pays 100%. This can be very significant if you use a shipyard not at your home dock. Situation boat won't start or you got towed back to your home dock or limped in. Service facility is 15 miles away. I've known too many people regret not spending that $22 more. In my home area of Fort Lauderdale a very small percentage of people get their boat serviced at their dock location.
As one noted, the quality of providers from port to port may differ significantly. The Captains are businessmen, mostly very good, some few not so good. If you boat largely in your home area, Id definitely talk to the owners/captains for Seatow and TowBoat US in your local area before choosing.
One other service available to anyone, member or not, but makes one want to be a member just as appreciation. That is information. These tow captains are often the best source of information on local conditions. They typically know ever shoal, every changing channel, the current condition of the inlets. They're out there plus they're assisting those with problems who may be the first to discover additional shoaling.
