Superfluous: the "self-cleaning" of the filter. The regulation of Sauglesitung, I know really no one who does not always use the highest performance.
To maintain peak performance you should definitely use the different nozzles, as I have noticed significant differences.
Conclusion: 449 I would not spend on him, for he is 254 solid and confident.
How long can rely on him and what wear will not be clear terms over time.