I have the Ova 8   25  foot poles,quality poles and well worth the money,had the SLX  poles which are great but got fed up with the reglueing of clamps and spinning  sections.
Still use an  SLX  30  on some jobs and although it is 5 feet longer it feels a lot heavier than the Ova 8  25,but funny enough don't feel there's much difference  in weight compared to my SLX 25.
What I do notice  is that there is more of a flex when using  extended and  at an angle like doing windows above a conservatory roof  from the side which is beneficial to me,
Because the sections are more of an oval shape but are not 100 percent oval  there is more flex from the side rather than upright  if that makes any sense.
All in all a brilliant pole and will buy another at a longer length,don't know if there is extensions like  Gardiner do.