interesting... so in itself, CQG is expensive depending on how and what you are trading.. BLP tradebook is more expensive
if you are spreading(cross exchange or multi-leg spreading), feel like trading yield curve by actually seeing it, would like to have access to pre-trade analytics, want access to really good order routing capability (granted that depends a lot on your fcm really, but is there!), want to be able to place dom-triggered stops and entry that will only execute given a depth (not just because trading took place and only 5 contracts traded at that level lets say), proper icebergs, Study-following orders on the DOM, being able to sweep the book, see your time and sales order aggregation on the DOM (i really like that feature)... then it isnt expensive given it is a cost of doing business...
but if you are doing the same old things that most retail is, then sure.. it is expensive given multicharts and ninjatrader are way lower cost...
so, if you care about stability in your trading and any of the things above I stated, then it is the cost of doing business and you dont look at it as too expensive or cheap...
i've tried and I've owned licenses for pretty much every platform out there (did I mentioned I am a geek...

) and I prefer and choose CQGIC over anything else... I mean, there are features that suck and need work... their market profile for example (there are better choices out there like investor/rt and WindoTradeBlue) ... and their programming language for custom indi's leave a lot to be desired... and other nuisances that they are fixing thanks to their new director of trading analytics... but to me, if you want stable platform, CQGIC is it...
with TT XT... the charting sucks, i mean royally... I do like their ADL though and their MDT as well... specially knowing my estimated position in the queue... love that about MDT...
anyhow, most of the other alternatives are just unstable, depending on what you are doing... so I dont mind spending the $$$ that I am as long as i make more than that...
so for whatever is worth... besides, based on your P&L, you shouldnt care so much about spending less than 1% on the right tools... just my 2 cents...