As I mentioned here before, I have spent most of my Eve career in highsec empire space (2008-2010), and the last six months in nullsec. After leaving Querious, however, we (temporarily) relocated to lowsec. I have now, for the first time in my eve career, lived in lowsec for a while, and boy it sucks. It's like nullsec without the advantages of sov; it's like highsec without the advantages of Concord protection. Allow me to elaborate..
If you're looking for PVP, lowsec is not the best place to be, as shooting someone brings a hefty security standings hit - unless the other side engaged you first. And yet, if that happens - someone engages you - there's no Concord protection, at least none to speak of. These factors combined lead to a situation where the only ones freely engaging in PVP are lowsec pirates: they don't care about security standing and the lack of Concord protection suits them just fine.
If you're looking for some ratting, lowsec isn't the best place to be either. Sure, there are some battleship class rats here and there, but generally it's still just frigates and cruisers, with poor bounties. Earlier this week I even found myself looting a Civilian Shield Booster module from a cruiser sized wreck.. For shame! For crying out loud! I have seen one belt rat with a 1.1 million ISK bounty, in the past few weeks. There's quite a gap between nullsec and lowsec in this regard, even though some lowsec systems have a truesec that's quite close to some nullsec systems.
If you're looking for mining, lowsec may have something to offer - as I don't mine I can't really tell. I haven't taken a thorough survey, but as far as I can see it's mostly just the regular space rocks around here: Veldspar, Plagioclase, Scordite, Omber.. To be fair, according to Dotlan there should also be some Jaspet and Hemorphite around, but I am not sure how much and how valuable that is. According to a miner friend of mine however, in terms of isk/hour it's more profitable to mine Veldspar in highsec. Especially given the added risk of mining in lowsec. if you decide to do it, you need to have some sort of guard around: unless you have essentially cleared out the area and maintain some kind of protection, one of those dratted pirates might pop you at any moment.
The same is essentially true for running missions and complexes in lowsec - you need to be very alert, because you may be attacked at any moment. An added risk, when you could be doing pretty much the same missions in highsec?
Now that I mention them - complexes - that's another chapter. I've scanned down four, and they were either laughingly simple (frigates with a cruiser or battlecruiser as 'endboss') or impossible to do on your own (think 10+ battleships shooting at my lonely poor Drake). There didn't seem to be much of a middle ground.
So - PVP impeded by a security standings penalty but no Concord protection to compensate for that; ratting generally not impressive in terms of excitement and/or isk earned per hour; complexes questionable and seemingly a bit out of balance; mining risky and not really worth it according to those in the know.
Tell me - why would anyone want to live here? If you do, what's your motivation? What have I missed?