I bought my first Dyson last week out of sheer desperation.
Last year, I bought a large black rug from Argos - and nothing has been able to pick up fluff/crumbs etc from it. Not my upright vax brand machine. Nor any of the three other brands I've borrowed from family/friends in an attempt to find something. So I always just had to pick it up and shake it off, then sweep up the crumbs from the wooden floor beneath.
Anyway, I've bee saving and last week I bought a cordless Dyson V6 and it is excellent! picks up from the rug with no problem. Battery life isn't great. Think there's less than 10 minutes if you keep it on 'boost'. But about 20-25 mins if you have it on normal setting.
Have to admit, I've not even considered cleaning the filters etc but just had a look at the care booklet and it does suggest doing this every three months.
There is also a careline that you can call to buy replacement filters and other parts.
Is your machine out of warranty? if so, do you think you could call the careline and see what they suggest? It might just be a small new part that you need.
But out of four other brands that Ive tried, I definitely do think that Dyson has been best. Though can't yet give my opinion on how long it lasts.