All responses to music, recorded or otherwise, are of their nature highly subjective and personal. If you want a Mahler set with emotion overlaid on the music then you should get Bernstein/DGG. This set is in many ways its antithesis.
In a perfect world Symphony 1 would have the short exposition repeat in the first movement. Even without it this performance is one of the most bracing and satisfying that I know.
Symphony 2 is excellent except for the very end of the disc where the engineers limit the volume because of the difficulty of recording this work. Soloists are very fine, however.
Symphony 3 is one of my favourite performances of the work with a bright and clear approach. Movement #1 is particularly noteworthy for being held together at a fairly brisk pace without any suspicion of hurrying. The subesequent movements are most sensitively and poetically done.
Symphony 4 works extremely well, again at a fairly brisk tempo. This is an alternative to performances by Maazel, Szell and Klemperer. Freshness is the keynote again.
With Symphony 5 the direct and poetic approach produces one of the most satisfying performances that I know for Kubelik lets the music speak for itself. Part One is excellent, with a funeral march that never drags in Movement #1 and an explosion of angry energy in Movement #2. There are delightful "lifts" to the walz rhythms in Movement #3. The Adagietto is a little slow by 2007 fashion but very well brought off. Movement #5 is a racing and jolly rondo full of life-asserting vigour.
I cannot get on with either Symphony 6 or 7. In the first case I find the tempi too frenetic and in the second a mercurial performace is spoiled by rather hard recording of the strings in particular.
Symphony #8 is conducted with much sensitivity but I think that the sound, again, is not as clear or commanding as other versions (notably Sinopoli). This is not much of an adverse criticism because any recording of this work will only give a pale idea of what happens in performance.
I believe that Symphony #9 is one of the greatest interpretations on record. There is a wonderful sense of forward motion in the first movement (it is ANDANTE commodo and not ADAGIO)and the complex emotional response that this music produces in most listeners is achieved by letting the music speak for itself. The orchestral discipline in the other movements is expemplary with the Rondo-Burleske (#3)an outstanding performance. The three different tempi in the Scherzo (#2)are well defined. The Adagio (#4) again has a remarkable sense of forward movement and line which for me in no way detracts from the sadness of the music. The ending of the piece is particularly moving and sensitive (this movement is played in the tradition of notable performers like Bruno Walter and John Barbirolli). This symphony is one of the best recorded in the set.
The one-movement "Symphony 10" only makes one wish that Kubelik had recorded one of the "completions" that we now can obtain so easily.
Words like "poetic", "sensitive", "clear", "brisk" and "exciting" occur to me when trying to describe the impression Kubelik's performances make on me. Throughout the set the playing of the BRSO is very fine, and the CD incarnations of these symphonies is in much better sound that the original vinyl discs. I believe that it is vital in Mahler to have an orchestral layout that splits first and second violins left and right across the stage - the first subject of #1 of Symphony 9 is given to them, for example, and in the music that requires clarity the stage-set for the BRSO provides it aplenty. Kubelik's was a great musical mind that allowed the emotion in the music to speak for itself without descending into the frigidity of Boulez or the occasional dullness of Haitink (though not in Haitink's superb Symphony 9 - only spoiled by not having split violins, in my opinion). Overall this is a fine set and a central recommendation - unless you like the cloying emotionality of late Bernstein or the interventionism of a conductor like Simon Rattle.