As always it depends on how and what you ride. My experience of fork changing on my 2008 TranceX may advise:
It came with an F120 QR fork – light and plush but ultimately rather noodly compared with the rear-end. Last year, I put a 150mm Sektor air on it – still light and plush but stiffer. At recommend pressures, the front sat-up to much for pedally riding; the BB was too high too. So I lowered the bars and ran the fork soft so it sagged a lot – this helped to an extent, but on climbs the fork extended and felt wrong, and the front was quite mushy even with compression damping turned up.
I recently had the fork reduced to 130mm and reset the pressures – vast improvement in agility, pedal-ability and climbing is OK again. It still descends well. But if you are just riding it downhill, maybe it will be OK with the long fork.