I prefer a well designed linerlock for ease of unlocking and closing the blade with one hand. However, for left and right handed use I'd prefer Benchmade's Axis lock folders and SOG's Arc lock folders.
It really depends on the manufacturer's design as one company's liner-lock is more reliable than another's lockback; and vice-versa.
In general, and all things being equal, I prefer liner-locks as they are easier to open and close. Although, I tend to stay away from the topic of "self-defense carry", I find that liner locks will deploy faster and with more certainty than a lockback of similar design.
I find liner-locks, as long as they are made properly, are more secure. There are exceptions of course as Spyderco, Cold Steel, and SOG all make very good lockback designs IMO.
The only thing I do not like about a lot of liner locks is that the blades will accidentally dislodge easier since there is no resistance of a backspring as in a lock-back, or even an Axis.