Oh do I just love these conversations, you learn so much in so little time. Couple of things about the above stuff I'd like to throw out there.
As to water/lava stopping frame machines, there are XyCraft blocks coming that act as water source blocks you can put in a square around the back of your block breakers to just turn everything into obsidian on the way down. Also, a good turtle tip is if you use the right control button, you can use ctrl+v easier.
Now, onto breaking things!
I've always found the best system is to use all available systems. With the TE distribution of ore, Tunnel bore's lost a bit of weight, as it would take a very, very tall bore to get all of the resources. So, you're looking at the following to be equal.
16x16 Frame Quarry
4x 16x4 Tunnel Bores
16x16 BC Quarry
16x16 Turtle Grid
9x Steves Carts (Preferably hardened drill head or higher) (Note, this makes a 9 5x5's, so an effective 15x15)
Now, in terms of resources...9 steves hardened drill carts and all the tracks for the...yeesh. Next expensive is probably the BC quarry, but has the upside of almost purely vanilla materials. Tunnel bores' will take a fair amount of brass, i.e. tin/copper, but don't require constant fuel. Turtles are by far the cheapest, but do require fuel. (Recently found out that RP picks work in place of a diamond pick)
As far as speed, Steve's carts are actually fast, but you have to temper that with it taking longer and longer to get back to your original cargo manager. A bonus though, they chunkload themselves with the right module. I don't have exact numbers right now for turtles, But a properly setup turtle can go through ~3 blocks in 1.5-~2 seconds. They can also be programmed to go forever as well as be chunkloaded, however, a chunk loading mining turtle can't be wireless, so to control it you'll have to start looking at more turtle to assist, and that kind of takes it beyond just a simple program. The new quarries I believe are faster than turtles, feels about 2 blocks a second, but that is at full 48mj speed. That's about 12 magmatic engines, or 1.2 buckets of lava per 10 seconds (Approximation, don't have exacts in front of me). Frame quarries can be as fast or slow as necessary, it can be more about interactions between machines than actual speed of the breakers. A layer every 2-3 seconds is usually adequate.
There is a third and even fourth part of this equation though. I'll get the third out of the way. Environmental impact. Can't really argue that a bc quarry or frame quarry remove large swathes of land. Tunnel bores and steve's carts, however, are under-earth, but that could be a plus or minus depending on what you prefer. I've seen a left alone auto-bore eat someone's underground base before. Imagine your surprise when you log in to find tons of machine blocks, rp2 machines, energy condensers, well, you get the idea, all in the overflow chest.
The fourth is perhaps one of the most important parts usually not added in, but trust me, it's the hardest and longest part. Planning.
I don't think I need to go into the planning needed to setup and get working a single steve's cart, let alone four. Turtles can actually take longer or as little as a few minutes depending on the complexity of the programming. Frame machines and tunnel bores are similar, it can take a long time to get every cover and panel just right, but tunnel bores are a bit easier by nature now, you can probably setup four as fast as a single frame quarry. The least time is the BC quarry, but depending on how elaborate you want your power setup, that could also be very intensive.
Now some of you may have been thinking 'Hey, where's the IC2 miner!'. Well, we're talking about a targetted variable machine here, you can literally set it up to ONLY go after copper and tin, or just lead, or just silver, and go to town. It's not exactly fair to compare a machine that customizable on it's own to the above mass-mining methods.