Since you asked for "thoughts or other manufacturers suggestions"...
If there is a Sundance dealer in reasonable proximity to you, you might want to check out the Sundance Optima. I wet tested all your tested models, except the Limelight Pulse...plus a few more. For MY needs the Sundance Optima was the best choice. The Sundance Optima should be in the same price range as the Caldera Niagara and Hot Springs Grandee.
Wet-testing, dealer support and price are critical. IMO, the wet test is the most important factor, then dealer support, then price. You should be happy with the feel of the tub and the only way to know that feeling is by wet testing it first. Hot tubs are a luxury item and are expensive... ....too expensive to buy without trying them out first. Dealer support is also important, but if you choose a well made tub from a reputable manufacturer that stands behind their warranty, you reduce, from the start, the risk of having significant problems with your tub. I think the tubs you've wet-tested fall into that category of reputable manufacturer with good warranty.
No matter how well a tub is made, there's always a chance of defect(s) and/or malfunctions. Even if all parts work perfectly for years, eventually parts, pumps, heaters, etc., wear out and will need to be replaced. Your contact with the manufacturer will be through your dealer. This is where good dealer support is important.
Of the three factors, price is least important (IMO). We all have budgets and price is an important consideration, but... ...if you buy a tub that i) does not feel exactly right, ii) from a dubious dealer... just because the the tub is cheaper, then you'll eventually be very disappointed. You'll experience "buyer's remorse", more likely sooner than later, no matter how low the price.
Of course I would encourage you to get the best possible deal you can. But I do think 99% of the time, we get what we pay for. You're going to have your tub for years (most likely 10+). A few hundred dollars (or even a few thousand dollars) more to get the tub you want and quality service you can rely upon will not be a significant additional per diem cost when amortized over the life of the tub. Getting exactly what's right for YOU will reap far more benefits than the momentary savings (IMO). You'll be happier physically, emotionally and psychologically (unless you're the type of person whose REAL pleasure in life is simply the joy of saving money).
Good luck with your tub purchase.
gman