Charlottesville Area Masters of Real Ale

Hi all,
I've recently broken into all-grain brewing, and I think I'm ready to make the jump from the kitchen into brewing outside.  Can any of you outdoor brewers give me some feedback on propane burners?  
From what I've seen on other forums, Bayou Classic seems to be the major brand.  I don't have any welding ability, so I definitely need to get something prefabricated, with burner and stand.  I'm trying to decide among a few models from Bayou Classic:
(1) the SP10: 14 inch surface, 20 psi regulator, 185k btu's, $55
(2) the SQ14: 16 inch surface, 10 psi regulator, 55k btu's, $50
(3) the KAB4: 17 inch surface, 30 psi regulator, 210k btu's, $80

Here are my other factors: I've got a flat-bottomed 15 gal. ss kettle, so I'm not worrying about a wobbly keg placement; I'm mostly doing 5 gal. all-grain batches but want the option to move up to 10 gal. batches some of the time (say, 25% of my brewing), which means I'll need to get 14 gallons boiling; I want to heat things quickly (my gas stovetop is so slow and weak for 7 gal.s) but I don't want a total propane hog.

Can you folks share some of your experiences and thoughts?  What are the boil times with your setup?  I'm leaning toward the KAB4 since it can better heat a 10 gallon batch, plus I don't want to do another upgrade after this purchase.  But I've seen some dissatisfaction on other forums.  In particular, people think the burner on the KAB4 is positioned too low to be as efficient as it could be, so some have rewelded the burner into a higher placement.  However, a lot of those guys are brewing in kegs, so maybe a flat bottomed kettle like mine would do fine.

In any case, thanks in advance.  

I have an SP-10... works pretty well for 5-gallon batches using a 36 quart pot.  It brings 6.5-7ish gallons to a boil relatively quickly, and given the combined price of it and the Bayou Classic pot that I got off of Amazon last summer.  I did some looking at pricing and found that Amazon was the best price with shipping included...

I haven't tried the other burners, but based on my review of what I could find online last year, I went with the SP-10 and have been happy with my decision...

5-6 batches per 20lb cylinder... mixed with a little light grilling...

-Brian

If the burner is close to the pot then it will hit the pot and spread radially, which means that the diameter of your pot does a lot to control the flame distribution. I can see where if the burner is too far from the pot (like you say for the KAB4) then the heat won't distribute well across the bottom of the kettle.  If you look at BTUs/$ then the SP10 is by far the best deal anyway(3.36kbtu/$ vs 1.1 and 2.63). I found a number of forum threads where people say even the 55kbtu SQ14 will work for 10gal batches. But for $5 more, I think you'd be crazy not to go with the 185kbtu SP10.