If you're passing on a blank 3/2 like Project Yagi-Uda, I'd pass on this as well. It's a uniquely clunky effect for a 3/2 and totally unsuitable for the 3x Spin Doctor role of instantly protecting agendas faster than the runner can react. A 3/2 agenda will never be instant anything.
All of the other unique 3/2s have much stronger abilities which are almost always impactful. Longevity Serum is not much better than blank. And, worst, when you really DO need Longevity Serum's effect, you're probably in a dire flooding situation, usually a hard time to score an agenda safely. Even attempting a Longevity Serum play to clear a flood leaves your extra agendas vulnerable in HQ at least 1 turn longer than they would have been with a Spin Doctor. I think this effect would probably be more suitable for a 2/1 agenda.
I would only choose this card in decks where trying to score 4/2s would be too hard (e.g. Shipment from Tennin decks can use it to recycle Shipment from Tennin back into the deck). If you can score 4/2s, it doesn't make sense to cut a 4/2 to include this card -- any combination of Nisei Mk 2, Cyberdex Sandbox, Corporate Sales Team, Offworld Office, and possibly even Viral Weaponization are stronger.
Note: Longevity Serum might have off-brand use in Ampere. Ampere can only run 1x Spin Doctor and might actually benefit from backup recursion. Ampere also has better access to fast-advance cards and economy than Jinteki has, so a 3/2 is inherently more interesting to Ampere even if the ability isn't always valuable.