Paul,
I searched for about two weeks before I purchased mine. I must have read every post here and the BBQ Bible forum in regards to digital thermometers. I ultimately decided on a Nu-Temp NU-701. Because of the "supposed" range that it has over the Maverick.
This is a heated discussion because there are fanboys of both. You'll get one person that says Maverick had terrible range while another person will say the complete opposite. I ended up purchasing the Nu-Temp because from the research that I had done more people consistently said they had good luck with range with the Nu-Temp. That's not to say that I didn't find anyone that didn't like the Nu-Temp. There seems too be more people pleased with it compared with the Mavericks.
Also, I like the fact that the Nu-Temp has really large readings on the display. You can see it from far away. Mine has awesome range from the back of the house all way to the front through several walls and obstructions. It's got a high and low alarm. It's simple and does what it needs to do. It can handle three probes. I like simple reliable things over bells and whistles.
I also liked the fact that I was able to reach someone right away on the phone with questions in regards to the Nu-Temp. I know Nu-Temp sold high temperature probes as spare parts but I don't see them on their site now. They were back ordered a while back. They intrigued me because they were rated very high for temp. They could most likely handle grilling applications.
As far as the probes and using them between the lid and the cylinder. I've had no problems. I too had concerns about the high heat on the edges of the grates and cylinder and the lid crushing the wire but haven't had any issues yet. I roasted this years turkey in the 350 to 400 degree temps for 4 hours without issue if that helps.
There are some things that I would advise for the care of probes. Never get the wiring wet, if they do, they can get ruined. A hair dryer is great for drying them off. Never immerse the wires. I only wash the solid metal part of the probe. Do not wash the wire if it get dirty. Just wipe them after each use with a towl or paper towl. Also try not to kink the wire. I store mine by looping them and secure with a twist tie. I try to use fresh batteries in my unit. It's a pain but I take my batteries out when not in use. Ever see that battery crud on the contacts after you've left batteries in something for too long.
I also think its a great idea to use a analog thermometer for backup. I just stick my analog with clip inside one of the top vents. This does not require any mod to the WSM, just bend the thermo clip out a little so it will fit a little tighter in the hole. Only draw back is that the top vents have little to no adjustment. Not an issue for me since I've never have had to adjust the top vents.
I spent a small fortune on analog/dial thermometers. The one I always use is a Pyrex I got from Bed Bath and Beyond.
Here's a photo.
It's nice because it's got a black background with letters. It's very accurate too. It was the most accurate out of the 5 that I bought. It compliments the WSM very well. Keep in mind that it's darn near impossible to have two thermometers that will read perfectly the same all the time. All you can hope for is to obtain ones that are close as far as boiling water and ice water test and adjust your cooking accordingly.
Good luck on your thermometer search whichever one you decide on!
Jonny