The Premium Terminal is nice, but heaven help you in the event of flight disruptions. I had a situation a few years ago where our 3-class aircraft was downgraded to a 2-class aircraft due to a tech problem (and 7-hour delay to boot). As a result, they had to downgrade First Class pax to Business and some Business Class pax to Economy. This was handled with no subtlety at all - an agent walked around with a security guard and advised of the downgrade, together with a polite reminder that as we were now in Economy Class we would need to leave the Premium Terminal in 15 minutes. The Security Guard would assist us if we had not lined up downstairs with our luggage by then.
What is even more outrageous though is that every single one of the passengers who were downgraded were of either South Asian or Filipino ethnicity, including a Gold Elite and a Silver Elite (myself). Some non-status Caucasian passengers who had been op-upped however were left in the Business Class seats we had paid for!!! And the only compensation received was a measly 2000 miles (in addition to the fare difference between Biz-Full Fare Econ). I subsequently (on a later trip) was shown a portion of their standing instructions that clearly specify ethnicity as a factor to consider when performing upgrades or downgrades.
So yes, Qatar Airways has a nice product and provides a pleasant experience, provided you're White or Arab. If you are Indian or Filipino, its a whole other story when things go even slightly wrong.
Note : I have other biases against Qatar as well. I once spent 2 hours in a cell at Doha airport with some of the most miserable and emaciated humans I've ever come across because somebody in immigration transliterated my name into Arabic badly and they couldn't find my visa in the system (I was on a Government delegation so had an "Official Visa"). I've also been warned by a Qatari security guard at Doha airport, when traveling with a Ghanaian friend, that I should be careful of black people because they would traffic drugs and steal from me. Quite possibly the most racist and pompous state I've ever visited.