I also play SHIII, and at the moment its probably the best simulation of the Battle of the Atlantic to come out since Aces of Deep.

Having said that it is also the only simulation made recently and it is not without its problems. You will need the patches as the previous poster suggested and then you will have to start applying modifications to increase realism. One of which is the Real U Boat mod posted above, which is not without its problems.

Right now the game has alot of issues concerning accuracy, I guess its one of the problems when companies undertake a game like this to make short term profit, and dont devote as much time and effort as they should to serious historical research, for instance the developers seem to think the type VII C/ 42 was actually built and operational. As it stands a number of critical systems don't operate correctly in the U-Boat, most obvious being the incorrect ranges on the Metox, Naxos and Tunis detection systems. Also airpower in the game is still an issue being worked out by a mod, but it was awfully easy to shoot large numbers of aircraft (30+ on average) down in the stock game with just the 2cm Flak on the type VII C. Other things notably absent are Leigh Lights from 42 onwards, FIDO, Sonobouys etc and patrol zones that have no bearing on historical events (i.e you aren't going to the US East Coast for Drumbeat). Theres also no wolf packs or decently modelled resupply at sea (either from U tankers or surface vessels), and in the case of the former the lack of wolfpacks also means that you have no ability to use the D/F loop and perform beacon signals whilst shadowing a convoy.

I don't wish to be a naysayer for the software, but you should be aware that there are alot of irritating problems which need fixing for someone really interested in historical detail and accuracy.

The good news is there is an active community for SHIII who are trying to iron out the many problems, I'm working on the radar dectors myself. On the downside though Ubisoft, the makers of SHIII, are no longer going to release updates and have yet to release the SDK (which would allow people to seriously reprogram parts of the software), allowing wolfpacks for exmaple.

It is worth buying because it does allow you to undertand better some elements of the U-boat war and the related technological aspects, but it also has a long way to go in some other ways. Hopefully too, casual users of the software will be encouraged to read more on the U boat war. On a final note, you will need a powerful system to get the best out of it, this means at least 1 gig of RAM and a good quality (read mid to high end) graphics card.