There’s no question that logging some time flying pixels on your desktop computer can help keep you sharp flying real instruments through real clouds. How much it helps depends on how sophisticated the simulation is and how you go about using it. So lets be crystal-clear that were talking about the bottom rung here: Whats the best choice for a simulator you can install at home to practice your procedures and scan in the half hour between cleaning up after dinner and the next episode of House? We should also set a few ground rules. You wont be able to log time for approaches flown without an instructor by your side, so we see no point in forking over big bucks for an FAA-approved system. You will want at least the basic flight controls, so expect to spend about $110 for something like CH Products Flight Sim Yoke. Helicopter controls might cost a bit more. We wouldnt bother with rudder pedals for airplanes. Plan on using your keyboard and mouse to control on-screen switches, knobs and buttons. 
ASAs On Top 9.5
ASAs On Top is not a game. Its purpose is IFR training and proficiency, and therein lies one of its strengths: Its simple. Big buttons and super-clear instructions lead you through setup and use. The program also ships with a chart-viewing program provided by FlightPrep. This has two advantages: Charts are easy to display and you have charts that match the navaids and GPS database youre using on the sim. Just like updating your charts in the real plane, flying a simulator with old navaids can be a problem as approaches change. On Top does have an airspace editor that lets you update the database manually.
There’s nothing fancy about the graphics. The instruments and avionics are not photo-realistic. The visuals for airports and weather out the forward windscreen are the barest required. But this made On Top the best performer on older computer systems.
Some additional niceties are that double-clicking any instrument will cover it (the program can simulate failures, too). The manual includes performance profiles for the nine aircraft to choose from. Included as we’ll are 10 instrument scenarios based on real accidents. Loading one will put you in the hot seat. If you can resist the temptation to read ahead and find out what the failure will be and just fly it, it can be truly enlightening.
The avionics are generic except for the Garmin GNS 430 and the G1000. The 430 uses a module built by Reality XP that leverages Garmins own 430 simulator so its almost a fully-functional 430 and is definitely up to the task of GPS proficiency training. Its the non-WAAS 430 and the database is several years old, however. ASA is planning on releasing a WAAS version but has no timeline yet. We hope they will keep the non-WAAS as an option but with a newer database for all the pilots who have not upgraded.
The G1000, on the other hand, is a facsimile of the PFD in reversionary mode (with power instruments on the PFD) and there’s no MFD. GPS control is actually done through an inset window running the 430 but using G1000-like buttons. While this may be useful for your G1000 instrument scan, we think its inadequate for real G1000 proficiency. Its also only available in the Cessna 182.
On Top had the least realistic flight model of any of the simulators. Thats good for your scan, but can be frustrating when trying to nail an ILS approach. Its not bad, its just that the other sims we tried were better. Adjusting the control sensitivity is easy to do but the options are limited.
On Top sells for $149.95. ASA also offers IP Trainer, which is a quite thorough training program for IFR wannabes, and Instrument Refresher, which is designed specifically to help pilots brush up for an IPC. Both of those programs include lessons and an On-Top-like simulator, but only for a basic Cessna 172. They sell for $169.95 and $79.95, respectively.
Elite 8.5
Elite is a major player in the certified flight simulator market along with companies like Frasca and Precision Flight Systems. But they are unique in that they sell the same core software