Short, easy, but the apartment is almost worth the time, even if it isn't worth the money.
Otherwise, the official review has this pretty much pegged. It's disappointingly short and unpolished, especially when compared to the "Bring Down the Sky" content expansion, which I felt was maybe a little short but was easily redeemed by being arguably the best mission in the game, with a fairly nice reward, to boot.
Pinnacle Station feels like something that was done by a tiny team of developers whose roles were zombified into DLC support for Mass Effect 1 until it was too late for them to meaningfully contribute to Mass Effect 2.
I guess my real question is why did Bioware release this in its unpolished form for Mass Effect 1, instead of finishing it properly and either making it part of Mass Effect 2 or releasing it as DLC for Mass Effect 2? It's hard to believe that someone estimated that this would move enough units to justify the development cost this late in the game's life cycle.
Edit:
Of course, finding fault is easy. More challenging is trying to turn fault-finding into constructive criticism.
I think Pinnacle Station could have used more role-playing opportunities through dialogue. Also, while the reward for completing the expansion is certainly reasonable, there is no further reward to re-playing the combat arena's virtual scenarios asides from trying to beat your own best score. Significant replayability could be added if your team earned experience in the simulator (which they don't seem to, I learned after loading an older save with level 59 characters), or if you earned cash or loot for replaying them.
One could try to argue that these additional rewards would imbalance the game, but I can't imagine that Bioware was concerned about the consequences of introducing unlimited resources into the game.
First, any level 60 character can quickly amass the maximum amount of credits and omni-gel very early in the story by selling or recycling unneeded level 10 loot.
Second, unlimited XP gains could easily be mitigated by reducing the XP earned in the simulator in the same way and amount that XP is reduced in the Mako, requiring a player to invest just as much effort trying to earn the "Extreme Power Gamer" achievement through the simulator as they would by playing through the story twice. In fact, they would need to invest a lot more effort earning the achievement through the simulator, as the Mako reduces XP gains to 1/3rd of what they would normally be on-foot.
Don't believe me about the XP loss in the Mako? Find a group of Geth with multiple Geth Colossi (yes, that's the proper plural of "colossus"). Destroy all but one of the colossi with the Mako, taking note of the XP you gain from each one. Reduce the last to a tiny sliver of health while in the Mako and then jump out of the Mako for the killing blow. Any sniper rifle is a good tool for this, at any point in your character's progression. If you have them, HMWSG Xs are also fine tools.