The first one is well worth your time. I still pull it out from time to time -- it is very challenging. They were both niche games that got Sony backing and became part of the Sony Value Line -- PS1 games that were first run, but discounted to $29.00 because Sony liked them and wanted to promote them.
The 2nd one has terrible English VO, and they made critical changes to the stances which weaken the overall experience. They also disposed of the "one large map" model in favor of smaller maps, which I found a little frustrating. The overall gameplay was simplified for mass acceptance, while adding more varied characters. The VOs are a deal killer though -- but it is worth looking into.
LightWeight, who developed the Bushido Blade series for Square, was subsequently bought by Genki, and went on to develop "Kengo: Master of Bushido" for the PS2. Kengo was very underappreciated, moving to historical characters in the Samurai era, and mistakenly eliminating the one-hit kills. Again, the perception of one-hit kills was thought to be unpopular by the developers. Some have claimed this game was a PS1 port to the PS2, but that is crap -- it is just a very, very 1st gen PS2 game without a lot of polish -- still a lot of fun if u liked BB1 more than BB2. Kengo 1 is really just a fighting game with no pretense of story at all, but adding a series of mini-games to build your samurai's attributes.
Kengo 2 made a Japanese and EU debut (2 years later after the JP release, by UbiSoft), but never hit the US. Crave had US rights to the title, but dumped it when it reorganized its business to focus on distribution and budget titles. Kengo 2 introduced famous Samurai from history, added a storyline back in, and brought back the 100 Kill mode. One-hit kills also started their return to the series, but more-so in Kengo 3.
Kengo 3 was recently released in Japan and expanded upon the overall experience. Kengo 2 and 3 both added multiple enemy fights, story lines, and more characters and modes. The Kengo games have all been best sellers in Japan, graduating to the "Books" greatest hits series.
Genki also has a second samurai series based on the Fu-un Shinsen -Gumi. One title is out, the other pending. Both feature character designs from the character designer of the Metal Gear Solid series, and are more mission based.
If u are interested in the BB series, the "Way of the Samurai" series from Aquire/Spike, creators of the orig Tenchu series on the PS1, is the inheritor to the throne. The first game is great, though a little unorthadox. It is like playing a Kurosawa movie, except for the Afro on one of the NPCs -- almost like a JP GTA.
The 2nd WOTS is even more GTA/RPG like, but did not do well at all in the US. Capcom handled the localization and bascially dropped it after it released it. I dare u to find mention of it on the Capcom Web site anymore. The VO sucks. It is damn hard to find at CAG prices.
The latest WOTS title is going to be released in the US by Atlus as "Samurai Western," and basically continues Aquire's tendancy to start off strong with an intellectual property, and then screw it up by the last release. The game has reviewed poorly. I'll probably still buy it though.