Choosing the right "business class" product
A few of my friends were talking about the cost of airplane tickets and how paying cash for a lie-flat seat was insanely expensive. Of course I had to give my plug about travelling on points and miles blah blah blah - but color me confused when they asked about how I could get the same $10k seat for just $900.
Then it dawned on me - they were searching cash rates for FIRST class. They simply didn't know that "Business Class" (which is only about $5k roundtrip) was what they were looking for - lie-flat seats, good food, and lounge access.
But I don't blame them - there's so much complexity here. Domestic flights only have First and no Business seats, except for premium 3-cabin transcontinental flights, but including repositioning flights using the same 3-cabin planes as 2-cabin flights. Confused yet? Yeah, it's not easy to keep track...
Similar to my previous post on choosing the right airplane seat, picking the correct airline is just as important.
How things changed over time
There definitely used to be a clear distinction across the board between Business (J) and First (F) for all airlines to all destinations. J seats meant wider seats with much more recline, while F seats were the only ones to fully recline into lie-flat "bed" seats. But then slowly J products began to improve, F stayed the same, and airlines found people were a lot less willing to pay $6k more for a F seat when a J seat was just as comfortable.
Over time, Premium Economy (PY) entered and filled the gap of the old J seats, J became the new F seats, and F cabins were eliminated altogether. Today, when you hear "Business", you should typically think of international long-haul lie-flat seats. When you hear "First", you should typically think of domestic recliner seats at the front of the plane.
But wait! There's exceptions! (Aren't there always exceptions?)...
The problem with labels
Simply put, there are far too many different products to create unique names for everything. It makes booking travel way too complicated, hence why airlines stick to the traditional Y, PY, J, and F booking labels.
But see the two images below. Do you see a difference? Which would you rather fly for a transatlantic trip?


The first image is Icelandair's Saga Premium class, which are recliner Business Class seats retrofitted on all their planes. The seats are wider than economy, the legroom is a lot better, but the seat simply reclines a few extra inches.
The second is the Delta One Business Class Vantage suite product. It features a fully lie-flat seat, premium bedding, upscale dining, private suite doors, and Delta One lounge access (which, by the way, might be the best lounge out there).
Two wildly different products, all marketed as "Business Class". Don't fall victim to the labels! When searching for a seat from NYC to London, don't book Icelandair thinking you got a great cheap price but only to find your seat doesn't lie flat, you don't get great food, and no lounge access comes included. You'd have to compare Delta PY and Icelandair J as those two products are more similar to each other.
My recent flight search
I was running some flight searches between Japan and India and found a seat from NRT-DEL on Japan Airlines for 40k miles. I then found another seat from HND-CAN-CMB-BLR on SriLankan Airlines also for 40k miles. The times for the latter itinerary were a lot better, so I was just about to book...until I examined the seats a little closer.
SriLankan flies A320neo aircrafts between CAN-CMB and CMB-BLR. That was my first red flag - we rarely see proper lie flats on narrowbodies as they're simply not wide enough to fit many. When I checked Aerolopa, my hunch was confirmed:

SriLankan was labeling a standard recliner seat as Business Class and hence was pricing the same as JAL's superior lie-flat J product! Phew - glad I caught that early.
How avgeeks differentiate hard products
When we are comparing different hard products (that's seat functionality, layout, whether it lies flat, etc), aviation geeks sometimes would resort to using product type names. You'll hear terms like "recliner", "compact staggered", "reverse herringbone", or "sofa seat". Each of those terms reflect a different kind of airplane seat and normally paints a really good picture of the aircraft design.
Some even go a step further and identify the specific product. Airplane seats are designed for a specific airline, but the airlines themselves don't build them. Terms like "Collins Aerospace" or "Thompson Vantage XL" narrow down the specific seat, where "Collins" and "Thompson" refer to the seat manufacturers. That's a little too complicated though, so I'll leave it alone for now. I've mentioned some of these terms in passing in my previous trip reports. See this post, this post, and this post.
I'll leave the exploration up to you. Bottom line is, don't just believe the label, always find a review if you aren't sure, and pick what matters to you most!