James Maliszewski of grognardia gives a good review of the Majestic Wilderlands. James comments reminded me that I haven't really talked about the results of the playtesting I did.
Once I started creating variant magic-users around 1990, rituals became an important part of my campaign regardless of the rule systems I used. To be honest I didn't know what the impact of introducing a ritual system to Swords & Wizardry would be until I started playtesting earlier this year.
Rituals definitely gives a more magic rich feel to the game but amazingly the resource management was still there. In the games I ran using S&W and MW the players were continually weighing whether to use a memorized spell or burn some of their limited spell components. The prices are set high enough that they just can't keep burning healing rituals after every fight. I am generally a bit light on treasures on my adventure but the resource trade off occurred even using other people's modules. (Ramat, Cave of Rot, the S&W quickstart, etc). It is hard to tell sometimes exactly what a rule does to a campaign without playtesting.
It still may be rituals are not for your campaign. The rituals definitely does change the feel of a setting. But you still have the resource management that an important part to early editions of D&D. So hopefully this will leave better informed whether it is right for your campaign.