Downtown (and LA in general) prices are up, per usual, inventory is low, and it's a Seller's market. Prices have well surpassed the 2007 height, and are now beginning to stabilize due to the holidays.
So what to do, BUY, SELL or HOLD?
Assuming you have equity, if you need the cash to upgrade, relocate or just to have liquid for whatever, SELL. It's a good time because prices are higher than ever before and buyers are pent up because inventory has been low for at least 12 months.
If you're buying to invest in the short term, don't. If you're buying to invest in the long term, then BUY. Prices are high, but they are going to be stabilizing into next year, so if you're planning on holding for a while (5-7 years) or you're sick of renting (I predict rental prices will continue to increase again next year in DTLA), then BUY. Why pay a landlord when you can pay yourself while gaining equity?
If you are not planning to do anything with the equity money, then HOLD. DTLA is getting lots of good investment in terms of qualified resident buyers, businesses looking to expand, companies relocating, and developers that are looking to be in one of the most unique parts of LA (e.g. The Row, At Mateo, Oceanwide Plaza). This will only help continued growth and revitalization.