James Conrad - David Finck’s book and DVD on making Krenov style planes is top notch. They cover the topic in great detail and clarity and goes beyond just making of the plane as well - sharpening, block plane tune up, making bench tools and more.
David Flynn - I can’t speak about building a traditional plane (though it is on my to do list) but I have built 3 Krenov style planes so I can fill you in a bit on that. They are not terribly hard to make (I did it without a bandsaw.) The great part is that you can easily customize the planes for your needs. I have a smoother with a Hock blade with a bed angle of approximately 53% - it can’t pronounce ‘tear out’. I also have a razee style jack plane that Ron Hock custom ground the blade and chip-breaker radius (for no additional cost!) - it is my ‘go to’ fore plane. I also have a smoother with a Lee Valley wooden plane blade which strangely doesn’t need sharpening very often. It is about the size of a #4 so I use it all the time for general work - I have a (terrible) modern Stanley #4 which I never use (it is the plane I give to others when they want to borrow a plane.) Bottom line - for me they don’t replace metal planes because they are a bit fussy to adjust, but they are a great addition, are fun to make, and the feel of a wood plane sliding over wood is great.
With regards to adjusting, use David Finck’s method for making the wedge. Actually get his book, and his article on (I think) Fine Woodworking. The article is a very helpful ‘summary’. If you pay attention to tuning the wedge the blade will hold so tight that it won’t shift in use. The other particularly useful part of the book or article are his instructions on flattening the sole. If you do it his way (don’t rub back and forth) you will end up with a dead flat sole.
Jim Matthews - The proof is in the cutting.
If you can get a good quality finish from a sharpened soup spoon - use that. If you’re set on making furniture, time spent perfecting tools subtracts from other pursuits.
I find that building the Krenov style Hock Kits is rewarding and quick. The critical step is inserting a solid cross pin to hold the wedge.
If that flexes or is eccentric, the plane will always be finicky.
FYI - I find the HNT Gordon planes a dream to use. They’re expensive, but work well, right out of the box.