Tar-X is an example of a 'different' tar remover. Whilst the majority are hydrocarbon blends of varying aggression, Tar-X is working on a different philosophy. It cannot be accused of being cheap and nasty (that is the reality of most tar removers in the UK - very few will pay good money so the manufacturers have no choice but to keep their costs as low as possible). Dodo is another one with a product which is a bit different - I applaud both companies for their willingness to offer users something 'value added' to their detailing brand products, rather than just selling the same stuff that gets used on industrial vehicles, but with fancy label, bottle and price.
The reason this type of product doesn't get the same attention is firstly the price and secondly, perceived effectiveness. This latter point was noted previously (though the posted might not have realised!). Faster removal is universally assumed to mean a better product. Think about wheel cleaners, what is the fastest and most effective cleaner? A strong acid product, probably with hydrofluoric acid. But, how many of us are using this on a daily basis? No one who would not be considered a joke on a forum like this! No, this product is wildly effective but that does not make it the best (it is also very inexpensive). Why is that? Well it is accepted that the acids are hazardous and can cause long term harm - they just are not necessary for most jobs. The same scenario exists with tar removers. I bet most people have no idea what solvents are actually in their tar removers. Ok, we know there is mineral spirits, but what else? Is your product equivalent to hydrofluoric acid?! Many times you cannot even find this info due to the failure to provide data sheets. Let me clear it up though, like with wheel cleaners, if a product works really fast and is really effective, it probably contains more aggressive solvents than a similar product which works more slowly. There are exceptions but most 'runny' liquid tar removers can be described that way. The boggle for me is that the detailing sector has decided that the faster a product acts, the better it is. Things like tarmalade or tar-x are milder, will have less risk of short or long term damage but the compromise is that they take a bit longer and cost a bit more.
I ask you, is detailing not all about doing a better and safer job, even if it takes a bit longer and costs a bit more?!
rops: I feel as if I might have been ostracized with great impudence some years ago (around these here parts) with my free willingness to use hydrofluoric acid. 
(And fear my lungs may have paid the price all the while.) 
That however was for maintaining rollback towing vehicles that I did not have the luxury of taking DAYS to detail. Sometimes it was just the aluminum bed by itself that needed cleaning (perhaps from hauling a burned vehicle) and that is by far the most effective solution. (Both in the sense it solved the problem and is a "solution".) Still have my stainless steel sprayer some 10 years later that I used to use on a weekly basis. 
