In an ideal world -- these would be identical, and from a purely electrical standpoint, they basically are. But, we live in the real world, where connections have parasitic resistance and badly made connections can do naughty things while in the process of falling apart due to vibrations etal.
The heatshrunk-over splice can be very good or very bad -- a properly made linesman's splice (also called a Western Union splice) is a robust creature, but is best used with solid wire as it does not work nearly as well with stranded wire. However, a poorly made splice has a habit of well, disintegrating over time -- and the ensuing arcing is quite the problem-causer.
The stacking of multiple ring terminals on a nut and bolt is standard practice when terminal blocks of that type are used -- it is a solid connection when performed correctly using a locking washer or nut. It does seem that that is absent from the terminal block in question; however, in the context of an appliance, I would leave it in the as-manufactured configuration (clearly, the maker isn't concerned enough about vibration shaking the bolted joint loose to put the lockwasher in).
The final termination -- a double crimp into a female tab crimp terminal -- is also standard practice in chassis wiring. When made using a proper crimp tool capable of ensuring a gas-tight, cold welded crimp -- crimped terminations are as reliable as any termination scheme out there, and do not care about solid vs stranded wire. In fact, they have a long history of reliable service in aviation and other such mission-critical applications. And considering the factory floor isn't going to use a $10 set of crimp pliers, this is the most reliable termination of the three.