I have the 24 gal. LRA and love it. I tow a fair amount and it really gives me great freedom to do what I want when I want. There is no sloshing at all. You will notice the pump noise when you first transfer fuel, that is normal and I grew to rely on it as an easy way to make sure they transfer was happening. The pump noise gradually fades as the pump is primed and transferring fuel (you can hear the pump noise greater on a turn when the fuel moves to the side if the tank is low, etc.).
The fuel transfer time for an entire 24 gal. tank takes about 15 minute in my experience, but this is not a drawback as I want a long lasting reliable pump--slow seems better for reliability. I had to remove my spare, but have not had any problems there either. I do now have onboard air and am an expert tire plugger. Barring total delamination or blowout, I should be okay there. I do carry a spare on certain trips and tows.
I felt trapped always having to worry about fuel and that may have been an irrational response, but it really does feel liberating to really not worry about when I have to stop.
There is one drawback that I did not anticipate, but it's minor. Most gas pumps are usually spend limited at $75 or $100. This means if I'm filling both tanks, I have to swipe my card again. Just a nit.
ETA: I would like to see the official testing or crashworthiness data from LRA or other tank manufacturers. I don't think I've ever seen it posted. Also, it would be nice to figure a way to transfer fuel out of the auxiliary tank if really necessary to give fuel to others, etc.