In the US, recumbents are almost exclusively a 40+ phenomenon, so I once asked the same question as the OP: how many 50+ rode them? By my recollection, not so many then as now. Unless you're simply looking for a 50+ opinion that you might trust, going into too much detail about them probably goes beyond the scope of this forum. If anybody is genuinely interested, the proper place to go for answers might be the recumbent forum on this site, or better yet, Bentrideronline.com . Bentrider is a large community with articles, reviews, and lots of members with opinions on virtually any recumbent built. Another site, recumbents.com, has a searchable database of recumbents.

Because recumbents are so different from uprights and even from each other, the almost-universal advice is to test-ride first. There are a few tricks to finding recumbent owners near you, including forums such as here, bikejournal.com, or bentrideronline.com, or local clubs and shops.