On the thermocouple, the one I have is a thin needle and it does react quite a bit faster than the food probes, but I am not sure if that is because it is a thermocouple or because it is a thin needle. TBHWY the reaction speed isnt a make or break thing, any of the probe types will work fine as the pit probe. The main benefits of the TC are:
1)TC's are available with much higher temp ratings, so if you do high heat cooks (like pizza, steak etc) you can use the HM without melting your probes.
2)TC's are available in very durable sealed designs that can stand up to moisture and steam and not die on you
3)TC's are generally pretty cheap compared to RTD probes
I have a kamado and I do use it for high heat pizza cooks etc, and had melted so many Maverick "High Heat Probes" that when the TC board became available I jumped on board and haven't looked back. I am still running the first TC I bought, have left it outside in the weather all summer and done plenty of high heat cooks (mine can stand over 2,000F!) so I am extremely happy with my decision to move over to TC....
There is one disadvantage to TC, you can't simply connect them to a CAT5 jack and send the output down a CAT5 wire. If you do that there will be a large offset in the temp reading that will vary depending on the ambient temp. You can, however, build an external TC amp and plug your TC directly into that amp and send the output of the amp down the CAT5 cable without any issues. I have been running mine like this all summer long and it works great.
