Solid, good features, but display problems
When pinch-zooming the chart there is a disconcerting spring back effect where it reverts to a previous size--and the labels jump helter-skelter between sizes. At a certain point, the display jumps again, the labels get HUGE, then settle back down.
Its really good otherwise-- a variant on the planetarium idea--this is a set series of charts showing you enough to star hop to key objects.
Take a look at Tri Atlas as well--also free, black and white area charts.
Of course this fixed chart approach may not be your cup of tea -- if thats the case go for for Sky Safari Plus, the best designed, full featured astronomy star charting++ app.
AstroPaul about
Star Atlas, v1.2.3