There are loads of Dyson repair "clincis" around for obvious reasons...:-)
Apart from the fact that a Sebo X4 is one of the best uprights you can buy (we've had one for several years), one of the few manufacturers with which Sebo can be compared has just introduced an uprights choice (S7) to its range for the first time.
Around a year ago I bought a Dyson DC19 from John Lewis for £150. I registered it with Dyson for their 5 year warranty and free tools normally around £35. To do this I spoke to their support team on a free 0800 telephone service.
The cleaner is the best cylinder type we have bought, with superb suction and cleaning properties.
At least ten years ago I also bought a DC04 upright cleaner. I recently stripped this down and dismantled the motor to check the carbon brushes. Hardly any wear had taken place.
Around two years ago I picked up the same model from a car boot sale for £25. Again I completely stripped it down. I found it had a new motor fitted and many other new parts.
A past friend who ran a repair shop always remarked how difficult these models were to service. Except for the old Junior and Senior cleaners, I have found Dyson cleaners come apart quite easily. Take pictures of the dismantling procedure if you are unsure of the assembly of the parts.
BTW. My wife uses the DC19 and the DC04 daily and she loves them.