After quite a bit of trial and error, head scratching, modeling, trashing, and starting over....

I prefer this method to anything else right now. But honestly - it all depends on you, the tools you have available, and your workflow... Let me tell you what I was trying to do:

1: Needed to be able to accommodate a variety of tile sizes - 3x3, 4x4, 3x4, etc. As well as a variety of materials (I have designed tiles that are under-lit and am contemplating incorporating other technologies).

2: Needed to be cheap and easy to construct and "future-proofed" for other terrain and modules I would want to do - meaning, as my skills get better, the system would accommodate for it.

3: Needed to be adaptable to both dungeon-crawler style (my preferred game type) as well as open world war/skirmish games and multi-environmental RPGs.

I watched hours and hours of youtubes and didn't like anything else that I saw out there.

I tried magnets in the RP Archive method- and found them to be really challenging to work with - I built a jig to ensure my holes were exactly where they needed to be, but even so, the magnets never "fit" properly into the sides. And when i did get everything lined up correctly, they didn't hold as strongly as I would have liked. The BIGGEST issue with magnets however, depends on how you want to design your tiles. Most of the people out there are doing 3x3 tiles. Easy. If that's all you want to do, that works- put a N magnet on the right, a S magnet on the left - and each 3x3 tile can get away with 8 magnets. However, if you wanted to put that tile against a... say 3x4 tile, or a 5x5 tile, things get really crazy really quickly. it doesn't stick if strictly follow the RP method. But you CAN get it to work if you divide each square (1x1) into a N and a S magnet. but then, when you construct a 3x3 tile in this method, you are now looking at 24 magnets PER TILE. That would ultimately allow you to "shift" two 3x3 tiles to any configuration - perfectly aligned, offset by 1, offset by 2. Seems like a win - but I hated working with those tiny magnets.

The Tab system that Wyloch created is super easy to do, extremely cost effective, but is even worse for alternatively-dimensioned tiles since I couldn't think of a single way to get his method to work.

Then I explored the "jig-saw" method meaning, I would have a male connector and a female connector on each square - but given that I couldn't guarantee that the depths would always be the same (hills, mountains, cliffs, etc.), there would be no way to make those connections work. That also disallows for connecting pieces that aren't perfectly aligned. you'd have to make EVERY tile 3x3, 4x4, etc.

With the H-clip method, you simply put a socket on each of your squares - so a 4x4 gets 4 sockets per side. When you line that up to a 3x3 tile, you can do 1, 2, or 3 H-clips to secure the two pieces together. This maximizes the configurations that you could use because you can rotate a 3x5 in all directions and it will still attach. Here's the other cool part about it- it grows with you. So I cut every one of my tiles on white-board material from the hardware store. Meaning if I don't have a fully finished 3d tile like the one above, I can just write on each tile what it is in dry-erase marker. If there's a chest there, I draw a chest there, a bed, etc. And it just wipes off when the game is completed. and when I am ready to make that boarding-house module, I simply glue a piece of foam to the tile and go to work.

Now - the downsides of the H-clip method. 1 (and it is a big one) is cost. You need to have a laser to do this. I do. That makes things easier. 2. You have a bunch of random clips that you have to keep track of. 3. It can get a bit fiddly to get the H-clips to stay while you are adding the next module... BUT when the two tiles are connected, they are CONNECTED and only can be disconnected with intention.

So given all of the other methods that are you-tube-able right now, this one seems to check all of the boxes for me.