I've only ever used Prime, and have had perfect success with it, no need to try anything else...it makes me wonder why API feels it necessary to have 2 different water conditioners...probably, to make more $
This is something of a side issue, but since you ask the question it should be answered.
API has been manufacturing their
Tap Water Conditioner for several years. It detoxifies chlorine, chloramine and heavy metals. This is the basic, and for probably 90% of aquarists it will be sufficient. Most conditioners do just this; I did find one some years ago that did not mess with heavy metals, but for most they deal with chlorine, chloramine and heavy metals. The benefit of the API over all others is that it is highly concentrated, and that means you use less to do the job.
API is now producing
Aqua Essentials, which detoxifies chlorine, chloramine, heavy metals, ammonia, nitrite and nitrate. This corresponds to Seachem's
Prime, though I have no idea if the two use the same chemicals/process to achieve the claim.
Prime is not the best conditioner, and I will not use it because it messes with things best left alone, and Seachem cannot (or will not) disclose how if asked.
API's Tap Water Conditioner is in my view the best and safest conditioner to use, if you are in the 90% who only have chlorine and/or chloramine to deal with. There is no benefit in adding more chemical substances that increase TDS and may have other impacts on fish long-term. The fewer chemicals and the least amount of the conditioner, the better for the fish.