I've used the stock kit seats (foam with standard backband), Hot Seat Grande (which I added on top of a piece of the standard 1" seat foam), and a Creature Comfort seat.  No expereince with Happy Bottom.

I actually put Creature Comfort on my first build (Shearwater Sport) and probably should have kept doing so. Although many more dollars, after a few hours in the saddle the money for a Creature Comfort seems well spent to me. I prefer the Creature Comfort seat for several reasons: 1) the backrest isn't a backband, and thus doesn't tend to ride up or down (espcecially no effort to "pull it up into place" as is necessary with a back band after cockpit entry).  2) The bottom pad is nicely contoured and fairly comfortable,  3) The Mesh web covering the bottom helps provide a little ventillation - less "sticky" when you're sweating. 4) The backrest is probably a bit higher than a backband, and the angle is easily adjustable (5 it adds a little extra support lift at the front edge under your thighs and makes the standard bent leg position a bit more comfortable - but I always add a gear bag or life jacket under my legs just in front of the seat for all seats anyways - just a personal preference thing.

On my second build (Chess 17) I started out with stock kit foam seat and backband.  Serviceable, but rudimentary.  After several excursions I decided to upgrade.

I then added a Hot Seat Grande bottom pad on top of a piece of stock seat pad withouth the stock "countouring" piece, keeping the stock backband.  That is pretty good and what I've been using for over a year. A little more comfortable than the stock set up.  It does put your butt up about 1.5 inches off the bottom - good for keeping dry, but probably not so good for stability (by a few minor percentge points) if you're worried about that.  I'll probably keep this set up until I strike it rich (or do a really long paddle) and spring for another Creature Comfort, but between now and then every once in a while I appreciate a ride in my first build (that is now my wife's boat) with the Creature Comfort.

I have no experience with the Happy Bottom.

   I have the stock seat with backhand in my Shearwater Sport. I didn't like the level of back support, so I now add a Coleman stadium seat right on top of it. It costs little to give it a try. I'm perfectly satisfied and can use the stadium seat to make my poly river boats a bit more comfortable too.

i've had great success with redfish kayak's pre-sculpted seat blanks:

https://www.redfishkayak.com/minicell-foam

at $75 its a pretty reasonable price for a very nice seat....you make the final cuts and fitting.

they also do a full custom seat and they are very impressive and i have put one on a high-end build i created for my wife:

https://www.redfishkayak.com/seats

the main issue i have seen with seats is not enough pitch (upward tilt going forward) to establish good support and prevent my butt from going numb.  i have also taken a 'hot grande' seat and shimmed up the front of it to create the pitch i am referring to with some scrap mini-cell and have had success with that.

h

I used to get very sore legs which eventually went numb in my Ches 17LT and that was down to the seat. I looked for advice and was recommended a Jackson Sweet Cheeks seat - basically an inflatable bean bag although you suck the air out to get a custom fit to your bum. It is excellent and adjustable for other users. Doesn't come with a back band.

The Creature Comfort seat is everything Bubblehead says it is, including a large-ish upfront price compared to other options. However, if you look at the entire picture it's worth it and actually affordable.

After getting my back and leg all wrecked up on an all-day boating trip in 2004 (it took 3 weeks for the pain to go away and to recover full mobility) I realized that I needed something better than a floating cushion to sit on. Doing the research, I settled on the Creature Comfort seat. Back then they were $90 each. I bought a pair of them so that my wife and I could each have one. They were the most comfortable seats I'd used and I've never had back or leg problems from sitting in a boat since then.

That was 16 years ago.  I no longer have the pirogue that I bought the seats for, but I still have and use the seats. They're easy to move from boat to boat and I do. I still use that 16 year old seat every time I go out in a kayak. It's been installed in a pirogue, a WD12, a CH16LT and it's slated to go into my WR16 when it's completed in a few weeks.

So the actual economics of the situation is that when you buy a CC seat, you're not putting that entire price into just one boat. It's a seating system whose cost is divided up over every boat it can go in, including ones you may not own yet. It's also divided over every year that you use it (in my case, 16 years and still in almost new shape). For me, that's less than $6 per year (less than 2 cents per day) and even at the current $170 it's less than $11/year (3 cents per day), which gets cheaper the longer you own the seat. It's also worth comparing the cost of the seat to the cost of seeing a doctor or chiropractor,  lost time, pain and suffering from a back injury and the cost of medications. 2 cents per day or less to avoid all that pain has been totally worth it.

The current price spread out over one year is 50 cents per day, so there's no need to win the lottery to afford one. Just skip something that you don't really need (soda, cigarette, latte, snack, lottery tickets, etc.) and put the change into a large jar. By next boating season you can buy a comfortable durable seat for cash without having to give money to the loansharks at the credit card companies.

Laszlo

Everybody's body and posture is different so there is a wide variety in what people find comfortable.  I have an entire shelf of kayak seats that I have tried in the quest to find what is comfortable for me.  We have the Happy Bottom in our recreational boats and find them comfortable.  For my race boats, I went ahead and spent the money for one of the custom seats from Redfish Kayaks.  Picture shows the seat in the Mystery.  I did the 31 mile Chattajack with no discomfort.  I did cut off the hip braces because there interefered with rotation.

   I started with a Happy Bottom on the bottom of the cockpit of the C-17. Lower back problems and knumb legs I raiseed the seat about 1" and it was better.  Went with that for four years.  One problem I found is that the standard seat is 14".  Mine is 15". 

I converted to Jackson Sweet Cheeks.  It works much better. https://www.riversports.com/rs/product_detail/12697/Jackson-Kayak-Sweet-Cheeks-Universal-Seat-Pad-100-200

My next kayak after the Jimmy Smith II will have a custom seat from foam like MarkN's seat above. I have foam already for that. https://www.clcboats.com/shop/products/boat-gear/kayak-seats-foam/minicell-closed-cell-foam.html

   I have the creature comfort in my shearwater it's pretty good but I'm going to carve a closed cell foam one. To get more thigh support