I like this tier-list of exchanges, it reminds me of the power supply tier list on tomshardware.com.
This list is a good start but I understand that it is based on personal experience, so obviously it's difficult to make it objective. So this list can be improved by community. My suggestion is to move Yobit to Tier 2, I've been using Yobit many times and never had a problem with them. Poloniex is in tier 1, I would agree with that few months ago, but not anymore. I had problems with withdrawals so Poloniex should be in Tier 2 at most.
Thanks

I downgraded poloniex;
i have to agree that the service sucks and i've recently lost confidence in this platform;
they owe me $50K frozen since about 10 days due to a "technical problem" with BCN web wallets and not a single response to my ticket. The interesting thing is that the bytecoin developers tell me they have been trying to reach them for a while to fix the problem but Poloniex never responded so there is something wrong happening here.
I'd like to put yobit in tiers 2 but the police investigation in Russia makes it highly untrustworthy; they could be shut down any time and all users would be screwed
I recently tried Tidex, which is a pleasant surprise so far; very neat and fluid interface; no verification needed, instant withdrawals and deposits
I have yet to reach their support for any problem but it is all good so far; just one issue is the low volume on most markets due to the fact that they are still a recent company
I added Kucoin which seems to be a nice company, transparent and legit for now; i exchanged emails with the business development team. I'll keep testing more exchanges and will try to keep the list up to date with the forum comments