Hi guys, I’m from Italy, so… forgive me for my poor English and my mistakes ;D
Well, I’ve been playing harmonica for over ten years. When I started I played lip pursuing only.
Now I can say my playing is about fifty-fifty. I can (but it’s not a rule) use Tongue blocking “in the middle” of the harmonica if I have to bend notes, but I can use it on the whole harmonica if I play “standard notes”. I cannot really effectively bend the 1st and 2nd hole and the 8th and 9th too (I have a weak, poor sound), so in this case I switch to lip pursue.
On the other side I can be judged a heavy tongue blocker because I play a lot of octaves, but also rhythm under the melody, opening and blocking the holes on the left and playing the melody on the one on the right, and slapping too. I love old time harmonica players (DeFord Bailey, Jaybird Coleman, Freeman Stowers, Peg Leg Sam and in general all the solo harp blowers of the 20s and 30s) and many numbers of solo harp must be played using a lot of tongue blocking ad chords.
But I play a lot of Chicago style too: I mean Sonny Boy (1st an 2nd who is my hero!), Little Walter, Walter Horton, Junior Wells and many, many others. I cannot say if that guys played 100% tongue blocking, like somebody says, but I believe that most of the times they used a mixed style. Charlie Musselwhite himself says he uses a mixed embouchure, depending on the riff or the number he’s playing. I also think Rice Miller uses a lot of lip pursue: if you look at some picture you can see he has his lips “heart-shaped”, typical of the lip pursue.
I think you can have a good tone both lip pursuing and tongue blocking, but tongue blocking is a must because without it you cannot play octaves, rhythm, slapping and other different effects. But if we talk about single notes, it depends on what you feel at the moment… I like use tongue blocking on single notes, but not always. On single notes tongue blocking can give you a better tone on attacks and when notes are played smoothly and connected on slow or not fast numbers. In the traditional blues you can hardly find fast and thousands note a minute. In very fast and not strictly bluesy tunes a lot of virtuosos play lip pursuing. Tongue blocking in “fast situations” is not effective because you don’t have the time to give the note the deep sound typical of tongue blocking.
Well, this is my modest opinion: “you have to play the way you feel”!
Keep on blowing, and happy new year!