Been using my Baofeng BF-F8HP Pro with the stock rubber duck antenna for about 6 months now, mostly hitting local repeaters. Getting decent performance but wondering if upgrading the antenna would make a noticeable difference.

Looking at the Nagoya NA-771 or similar aftermarket antennas. All handhelds have the same "Achilles' heel" - low transmit power and poor antennas, and if you buy a new handheld radio today, you'll get the same few watts output and rubber antenna as handhelds had four-plus decades ago.

For those who've upgraded - is the range improvement worth it? Any specific antenna recommendations for 2m/70cm?

I agree, a good antenna changes the game completely. I have a Nagoya 771 on the Baofeng right now. Works like a charm. The range increase is noticeable. Night and day difference for both receive and transmit on repeaters.

Absolutely worth it! Upgrade the antenna on your HT. If you are operating inside a car, use an external antenna on the roof. For home use, consider a small mag-mount on a cookie sheet near a window - dramatically improves performance over the rubber duck.

The antenna upgrade is one of the best investments you can make for an HT. With a better antenna, especially installed at height, you can probably reach quite a few repeaters and enjoy a much better simplex range, even with the low powered HT. I notice a BIG difference between my HT's "rubber duck" and a roll-up J-Pole.