Lucille Ball was a comic wizard, and any die-hard fan of "I Love Lucy" would tell you that her biggest comedic quality was her facial expressions and body language. Although many people felt Lucy was too old to play this role (and the many "soft focus" close-up shots in the film may be a huge indicator). Nevertheless, she played excentric, colorful and brash with perfect comedic timing and her classic hysterical pratfalls.
Add to this the completely PERFECT casting of Bea Arthur as Vera Charles and you really do have to give this film another chance. I know EVERYBODY says that the Rosilind Russell film is the best -- I LOVE that film also. But "Mame" is a retelling of that story in musical format, so it is very difficult to compare the two -- it's like trying to compare the musical film "Hairspray" with John Travlota in the part of Edna Turnblad to the original John Waters film starring Devine -- they are both enjoyable, but both very different movies.
The production numbers in the movie are done on a grand scale (I love the opening number, "It's Today") and although the film looks dated by some of the camera techniques used during the early 70's films, it stil holds an endearing quality about it that allows me to watch it over and again.
As a personal note, this movie became somewhat of a family tradition at my house growing up when VHS came out. Every year, after Thanksgivng dinner, our family would pop it into the VCR and enjoy a couple of magical hours together as a family, as we all sang along with the musical numbers and recited some of the funniest lines ("Vera, how old are you really? The truth, now!" "How old do you think I am?" "Oh, I'd say somewhere between forty and DEATH!")
Despite all its production flaws and perceived miscasting, I haven't ever been able to criticize this picture. If you really hated this film, try to give it another chance -- try not comparing it with Russell's performance and soak in the fun and the magic that Gene Saks was trying to capture in this story...it really is there!