Airlift Suspension??

NorthStyle

Yes, the AirLift (I'd recommend the 3H as it does both height- and pressure-based adjustments) can perform as well as most entry-level coilovers, but they do need to be setup properly. However, if improperly setup they can be floaty in corners unless that's how you want them to be.

What is your definition of "higher speeds"? For anything legal in the States, you'll be fine as there are cars here in Germany that cruise at what I'll label "autobahn speeds" without issue.

Air suspension systems do require a bit of maintenance, but nothing too serious. Mainly checking your lines every now and then for leaks as well as making sure they're in good condition; emptying your tank as water can accumulate in it and cause havoc on your valves (I have an electronic purge on my cup kit so I can do it at the press of a button); and the last major thing I can think of is checking the bags every now and then for rubbing/leaks/etc (same as previously with the lines).

The best source of information I've found for air suspension is AirSociety.net. A few people here are experienced with it, but EVERYONE there has it so obviously, the pool of knowledge is much deeper.