you are right Kytro, ;ots to learn and lots of options.
The thing is, a lot of the time, people say HERMS, RIMS etc as though they are all the same. They aren't. HERMS at least having quite a few variations, all with good and bad points.
You can have:
A Heat ex in your Hot liquor tank - with constant circulation. The element controlled
A Heat ex in your Hot Liquor tank - with constant circulation. The HLT is significantly hotter than your target temp. Temps controlled via valves which route the wort around the heat ex
A Heat ex in your hot liquor tank - you only circulate when you want to add heat for a step or to maintain temp. The pump is controlled.
A separate Heat exchanger with a small volume
A separate Heat exchanger with a larger volume
The temperature sensor in the Heat ex vessel
The temp sensor on the wort return manifold
The temp sensor on the heat ex outlet
A RIMS instead of a HERMS
and any combination and variation of the above options - plus all the ones I forgot to mention.
Spend some time researching and designing your recirculating system. Not weeks, months. There are a LOT of options and what you hear about first might not be the best or even the most widely used. Think about what you can best and most easily build and maintain. Be prepared to not get it right and have to change. Some people build a HERMS/RIMS and it works great from the get go - Others have had to constantly tweak, change and adjust... taking years to get things right. You may have to pay in time and effort, far more than the bit of extra money a re-circulating system costs - or you may hit it on the nose first time and wonder what all the fuss is about.
None of the options are necessarily better or worse than the others - I know for a fact that fantastic brewers use all of the different options I mentioned above. I know which one I prefer ... but Screwy or Schooey or Vossy all probably use a different variation. And they all work too. You really have to study them all and just go for the one that feels right to you - and be prepared for all sorts of self righteous pontificating from those of us who have tried it out before and think we have it right now - our way is obviously the best way after all. No matter which way that happens to be.
TB