The FX-951 is a decent iron. Its weakness when compared to the fancier ones (e.g. JBC) is that it cannot as easily dump gross amounts of heat. This becomes important if you are working with direct connections to ground planes – thermal relief on pins is inadvisable in RF and high-speed.
I have an FX-951 at home, but I am thinking about replacing it with one of these JBC compact stations (see below). It is double the price of a 951, but in this case I actually think it is more than twice as good. That is almost never the case – usually with expensive tools you are chasing marginal added value.
https://www.jbctools.com/cdes-precision-soldering-assistant-station-product-1531.html