Depending on the use the marker will receive
If you use your £200 marker once a month for maybe a cases worth of paint then i'd expect it to do an outstanding job of slinging that.
If however you use it 2-3 times and use 2-4 cases of paint each time, then you've got to ask yourself 'will this gun still be working reliably'
I shoot a proto trix, i have used a nyx, dm4(awesome value now), eclipse cocker and an ego in the past- i can honestly say this proto shoots as fast and is as reliable as any of those, i've landed on it awkward i've submerged it in a puddle by mistake and this thing keeps going and keeps spitting out the paint, i'm not sure i could of abused an ion (for example) in that way, or used it with the frequency i use this without having major support for parts.
MY opinion
A £200 marker is an excellent way for someone to get into the game of paintball - and compete equally, a player could compete at all levels with this provided they had good tech and parts support.
A £4-500 marker (second hand) will give you top level performence/reliability and quality for twice the cost, it might still break down but then parts are normally easily available and tend to be o-rings or seals. Also the futureproofing of these markers is achieveable through new boards and chips ( i believe the ion also has that)
A £500-1000 marker will give you this years top end gat (see above)
A £1000+ marker just gives you something a little more exclusive