Basically it is the electricians choice, whatever he/she is comfortable with. Personally, I find QO is more expensive than most and a PITA to wire neatly. SqD HOM and Siemens allow for much neated installations and are easier to work with.

I'm new top this forum, but I was reading your question, and thiught I'd reply. I'm currently upgrading to 400 amp service in my house. I chose to go with 2 Square D QO pannels. They are more expensive, but have a few nice features. The only one that you might notice is the breaker indicator. It shows red through a little window on the breakers only when one blows. It sometimes makes it a little easier to find the blown breaker. If you are instaling it yourself, you might notice the neutral bus bar on the QO line has some places to attach larger wire sizes. (for subpannels, furnaces, heat pumps and maybe waterheaters).

As far as quality, I think most are comparable, but I like Square D. I would think there breakers would be available for quite some time, it sucks trying to find breakers for pannels that are no longer made, like the Federal Pacific boxes.

Well that's just my opinion, and the question seamed to be asking for opinions, so I hope this might help a little.

Josh

I've wired in several panels, replacing older ones that parts were no longer available to buy. QO has been around, and will continue to be around in the future so that 20 years from now your box won't have to be replaced to add a circuit. From my experience, the small cost difference is well worth the build quality if you plan to live in the house. Square D is a decent line too if you're on a budget. Just stay away from GE.