I've been into subsims since the pinball arcade days and Silent Service, and have been playing this franchise since the first Silent Hunter.
At the time I liked Ace of the Deep slightly better (the campaign mostly) even though SH had SVGA graphics and a much nicer look. I still got a lot of hours out of it because of the different theatre and everything that goes with that. I still have the orignal CD but can't find the map packs.
2 was supposed to have interop with Destroyer Commmand, but Ubi never did fix it and it took a few dedicated individuals and modders many many months to get permission to finally fix it.
3 was groundbreaking in many ways (3d interior with crew being the biggest) but it had a lot of bugs (understandable, new engine and all) and Ubisoft dropped support after a few patches. Shackled with Starforce DRM. Mods make it.
4 added a few more features and switched back to the Pacific. However it was also bug riddled, some carrying over from 3. Ubisoft dropped support after a few patches. I'm not sure what DRM scheme it uses. Mods make it.
5 again added more features but the same annoying bugs return among new ones. It was and is shackled with always on DRM (the launcher has been patched and it no longer works in offline mode). Ubisoft dropped support after one patch (or was it 2? certainly no more than that). Mods make it.
See a trend here?
I do have to say that I have seen some of Ubi's individual employees really go to bat for the community (see community patch for 2, modability, etc.) and these individuals are great. Somewhere up the chain of command something is getting lost however.
It may have taken me awhile to see just how wretchedly Ubisoft, the corporation, treat their customers, but I'll never forget and more than likely never go back.
If SH5 didn't kill the franchise, this most certainly will, at least for people who want more than just an arcade shoot-em up.
Sign me up for kickstart SS!