Which Type Of Mash Tun

Seen quite a lot of cooler type mash tuns on forums etc ,
Now looking around and seeing stainless steel types also usually surrounded with Bubble foil wrap.
Simply is one better than the other? Does either have an advantage over the other?
Does the steel type retain heat as well as the cooler types do

Stainless steel is more durable and could double as a boil kettle. A cooler will definitely hold a temperature better unless you have some really impressive insulation on the steel.

I am probably the noobiest of noobs on this site, so take this for what its worth, but I just brewed my 3rd solo batch & 1st recipe of my own design (Oaked Honey wheat) on Jul 4th using a mash tun I made out of a 10 gallon round Igloo and the cheapest plumbing I could get to make the filter tube and spigot. Beer Smith said my OG was supposed to be a 1.052 on a double infusion; I hit a 1.053, but dropped my boil timer at one point and had to reset it based on an estimated time, so I may have over-boiled a bit.

I'm a firm believer in the efficiency of the cooler.

We use the foil bubble insulation in our cockpit sun-shields for the helicopters, and they're not efficient at all. Because of this, I think there would be too much heat lost in a SS Tun even with insulation.

I converted a 10 gal Igloo cooler to a mash tun with a bazooka strainer and I hold temps every brew day with no problem. I have heard nightmare stories about SS mash tuns.

No temp loss with these......buy they ain't cheap!
http://www.yeticoolers.com/

I'll second and third what these guys are saying. My first few batches were in a stainless steel pot, and I was reluctant to us a cooler mash tun. Bottom line, SS doesn't hold the temp well. I bought a 5-day rectangle Coleman cooler and parts from Lowe's to make a cooler mash tun (plenty of videos online to show how). I tracked my progress on Brewer's Friend and my efficiency went up a full 10% when I started using the cooler mash tun and batch sparging. Keeping the right temp during the mash has greatly accelerated my brewing efficiency.

I just made the jump from partial mash to BIAB AG, and I mashed my grains in and igloo cooler with only a 1 deg temp loss over 90 minutes. It also frees up my kettle to heat up the sparge water.

I use a Coleman Extreme cooler. It will hold temp within 1 degree for an hour. $35 for the cooler and about another $35 for a spigot and copper manifold. I bought the 70 qt. there is a good thread on this website on how to modify it.