The thinner a paste is, the easier it is to handle. However, other criteria are also taken into account here, because some pastes pull nasty threads when tearing off, which remind you of cheap Gauda on hot spaghettis. It is, of course, only a subjective impression, but it often says more than simple figures for viscosity. 
One should not expect miracles from (however expensive) pastes, but a significant improvement over the normal average. Nevertheless, in the end, it is often less important what you pay for a paste and what the manufacturer gives full-bodied for a theoretical heat conductivity. You get very good pastes even for acceptable prices and often enough decides in the end the right application alone about the failure or failure of the thermal paste exchange. So you can also be shipwrecked with expensive products if you make serious mistakes or capitulate to a paste that is too complicated to handle as a newcomer. Some pastes have been real long-distance runners for years and are also extremely inexpensive. So it makes little sense to invest huge sums if you could live the same way with 1-2 Kelvin temperature difference. Because one thing is also certain: Systems in which such a small temperature difference already decides on the life and death of a component are neither suitable for everyday use nor designed for use. It is definitely advisable to get in depth with the best pastes beforehand. because we can only make a recommendation from our own experience and the current measurements. There can and will be better products, because you can’t measure and select everything in the end. In addition, of course, the market is constantly on the move. Newcomers will certainly cope better with more fluid pastes, professionals will probably prefer good viscous pastes.
