Never seen a review, but mine would be:
Jeppview:
Basically an approach plate (IFR) display/printing package, with 28-day updates.
Hacked together about 10-15 years ago, last looked at in the days of windoze 95, nobody would buy it except for the data which is not really obtainable (in electronic format, on the retail market) any other way and which is very good. The data (mainly approach plates etc) is designed to display adequately on a 800x600 portrait tablet display, in flight. On the ground, it does a great job printing out a selection of plates and for that alone it's worth having if one does a LOT of IFR flight. Expensive to buy and VERY expensive to keep up to date, but (at a price) you can get plates for the whole civilised world, curiously including the UK military airfields, and all designed to the same style.
The latest, Jeppview 3, comes with another hack called Flitedeck which gives you a GPS moving map that automatically switches beween approach plates, en route IFR charts, and airport (ground) diagrams. A very slick product once you suss out how to use it.
Flitestar:
Basically a flight planning package, like say Navbox but with much more detailed VFR charts and various weird extra features. Very easy to generate a flight pack which has so many pages you will never be able to read it in the air! The VFR charts are IMV not detailed enough to eliminate the need for printed charts for VFR flight planning; they are not the same as Jepp's VFR/GPS charts. The VFR map data covers a much bigger area than Jepp's VFR printed charts but a lot of it is really bare. One can print off chart sections etc as part of the route data pack, to carry on the flight, in case the battery went flat etc.
3 updates a year, I think. The Euro IFR version is about £500 which is an almost reasonable price for what you get. The Flitemap version will accept NMEA GPS input to show aircraft position, which is very good.
A slightly more recent hack, too many quirks to mention (e.g. you can load in a planned route but it doesn't display; extra ops are required to see it and it could just display a different one instead), too fiddly to use in flight except as a plain moving map display (Flitemap) with simple route edits being possible.
Integrates with Jeppview so you can click on an airport on the map and see the approach plates for it.
Copy protection is quite strong. The software needs to run on a computer which can have a real physical CD drive attached (can be a USB one) for the updates; one cannot update it from an update CD elsewhere on the network. Lots of serial numbers to mess about with. Flitestar/Map runs with an out of date database but Jeppview stops running if the database is past 2-3 months (a very dodgy practice but one can get around it by setting the PC date back).
Basically, it's all cr*p software. But it comes with data which cannot be obtained any other way, which is updated regularly and is as accurate as you will get anywhere, and that's why people pay the money.
For heavy european VFR pilots it doesn't cut the mustard because it doesn't eliminate the expenditure on printed VFR charts (a stupid marketing decision IMV) especially as Jepp don't publish their Bottlang touring guides in electronic form. I would stick with Navbox for VFR; it's as good and is 1/10 of the cost.
Heavy IFR pilots like it, it offers a working and integrated solution which costs a small fraction of the cost of the flying.
Hope that helps. I'd go on a training course if I was spending the money, otherwise you will wonder what the hell such and such does.