MT Help Needed

This is my first post so a brief introduction is probably in order. I've been a wine maker for about 15 years and decided to venture into beer brewing. This forum has been an excellent resource to guide the design and construction of my brew stand and equipment. Thank you all for the generous sharing of your ideas and experience. My progress so far consists of a two tier stand, natural gas burners controlled by a Honeywell valve and PID. The next steps are plumbing my kettles, including a HERMS coil in my HTL. I have two kegs for the HLT and MT but am undecided about what type of container to use for the MT. I'm not trying to start a debate about whether a cooler is better than a keg, but instead I'd like to hear from users of both about what they DON'T like about their choice of container. I can see advantages to both but it is the disadvantages I'm less clear about. I think I have access to a third keg but could just as easily buy a cooler. Thank you all again for helping me get this far, I look forward to your opinions.

I started off using a cooler mash tun. A couple things I didn't like about the plastic cooler was it warped over time from the hot liquid sitting in it, and after a while it started picking up a smell that got progressively harder to get out. I switched from the cooler straight to a 20 gallon stainless steel pot. If your not direct firing a keg you could easily make it a bottom drain by flipping it upside down and cutting the bottom off. That's the one thing I wish I did differently with my 20 gallon tun would have been to put a bottom drain in instead of a pickup tube.

Thanks Chrisl77.

I used a 10 gallon round cooler for a year or so. My first brew warped the inside of the cooler, but this didn't change anything other than capacity. After several brews my O-ring seals started to leak around the ball valve, which really sucks when your mash tun is full.

I got a keg turned it into a bottom drain MT and silver soldered my fitting and have zero leak problems. I made a BCS control panel and made an eHerms setup to control my temps. Even with constant circulation the temperature control took a bit practice to dial in because the keg isn't insulated. So I insulated the keg with that silver bubble wrap stuff that they use on water heaters. This fixed all my problems with the keg MT and I would never go back.

Great answer, thanks for the input. I acquired a third keg and think I will follow along the lines of what you suggested.