Go Professional II
Go Professional II was a commercial Go playing program written by Michael Reiss? and sold by Oxford Softworks. It's been superseded by Go++.
Jan: I don't know about version three[1], but version two is (in my not so humble, 15k opinion) quite horrible. 'Computer level 1' plays only slightly worse than 'Computer level 9' and a lot quicker to boot. Only boring moves, no joseki, no problems, no hints with explanations, no nothing :-(. The graphics are nice, though.
[1]: I've heard Go Professional version 3 is quite strong, does anyone know more?
From my personal experience, Go Professional version 3 is quite weak, i havent had more time to play it, but the first game was lost to me by 2.5 at lvl9 - ZeroKun
GoranSiska Isn't Go Professional a commercial version of Reiss's Go++? I used to beta test the program but haven't received any new versions for quite a while.
Jan: According to http://www.britgo.org/gopcres/playit.html#gop2, it's indeed a published version of Go4++ by Michael Reiss. The review there is quite favorable; maybe it's just that the program's easy-going style doesn't work well against me. Your mileage may vary...
GoranSiska Well all computer programs seem easy-going to me :). Go4++ looked quite strong for a program at the time and it's stats in the computer tournaments is very good. I haven't played against Go professional though. The Go4++ betas we used to receive were the latest version of the program and I'm not sure which versions made it to the final product.
quaestor I can't speak to strength (I'm not strong enough to judge ;-), but the latest version is Go++ v 4.1, and is being sold directly by it's author, Michael Reiss at http://www.goplusplus.com/. I don't know what version of the Go4 engine is in Go++, but GoranSiska is in the about box ;-). (Okay, I'll say this, I'm about even at level 1 and about 20 stones behind at level 9...)