I'm a fan of Miele and Dyson!..
I've had 4 Dysons, the original DC01, then the first Ball, and a v2 cordless and now finally the V11 cordless (Always bought in the sales, even then quite expensive with £160 off!)..
I've also had 2 Miele vacuums I've bought for rented properties and used them quite a bit before/after each tenant..
I like the Miele for the simplicity and longevity, tenants don't treat them with care and they are still working after 7 years..
The Dysons I just rate for their cleaning ability, the V11 cordless is actually the only cordless I've tried that actually does replace the upright for us, loads of power/suction.
What I would say about all vacuums is that most people really clog them up with fine dust and they all lose quite a chunk of performance if you don't strip/clean then every now and again.. The V11 has easily removable/washable filters and I've cleaned it every 3 months and immediately on cleaning it the performance is notably better.. I can't imagine how many people probably never clean them and are missing out on half the performance, same goes for Shark (I clean my mums every time I visit, the before/after performance is staggering).
Personally on a budget the Sharks are fine, but honestly taking new (or newly cleaned) cordless vacuums, the Dyson V11 is really hard to beat, it's very much better than my Mums Shark and even better then our Mieles (Albeit slightly older models).
Each to their own, I have grown accustomed to Dysons plastic look, to be fair it's pretty durable, and refreshingly if we have damaged it through quite bad abuse I've managed to buy spares direct for good prices and found them easy to fit, they look cheap but on disassembling and reassembling they aren't that bad at all.