What many forget, and I confess I had forgotten, is that the Frieza saga and Goku's transformation into Super Saiyan is not merely the culmination of the 100-odd episodes of DBZ that have come before it, but also of everything that has happened since Bulma hit Goku with a car back in the very first episode of Dragonball. It's the next major step in a 20-odd-year journey and is a big damn deal for a little while. All that taken into account, I will admit that the Frieza fight drags on far too long, but, then again, I'll say that about most fights, even Goku/Vegeta and Gohan/Cell. The Frieza "five minutes" comment is annoying, and not easily ignored as it keeps getting hammered home like a major plot point, it's a shame because Frieza is really one of the best villains in the programme. A super-powerful space dictator whose strength as meant that he has never truly been challenged, his ego is such that he cannot even contemplate defeat and still refuses to admit that he's beaten when cut in half and bleeding out. That massive ego up against Goku's natural humility is a great match-up, no wonder he keeps coming back.
As much as I love Dragonball Z, the Frieza saga drags, not as much as all the Buu stuff later on, but still. However, unlike some other parts of the programme, there's pretty much no work-around, you have to watch it to get the story, even many of the episodes that drag on far too long. Frieza and Super Saiyans are important yardsticks for the rest of the series and the title fight is actually really good, just padded out the wazoo. Not much more to say here, I like it, I don't love it, but it's pivotal and if it's a deal-breaker for you, maybe just give DBZ as a whole a miss and try something else, One Punch Man maybe?