Hi,
it depends what kind of performance you are looking for. Fascina is a uPVC window company, that means the performance in general will be much better than local aluminium windows but it is also bulkier.
There are some slimline aluminium doors from European companies available, for example Skyframe from Switzerland. Vento System supplies them. This is very high end. Schueco, a German company, also has some fabricators here which can do a wide range of high end sliding doors.
Do you have other concerns beside slimline? How large are the doors? What kind of function do you want (multislide, soundproofing etc). All these things will influence what the best choice is for you. Hope the above company names help you, all findable via google.
