Let me get straight to the point; a slant bar is not a good choice as your first razor. It is however an excellent second razor.
The construction seems to be a mix of cast head and machined shaft, with a cast know on the end you unscrew to disassemble the razor. There is a split ring that should keep the bolt shaft inside the handle, but on mine that has loosened to the point where I can easily withdraw it for cleaning.
The 39C is a fairly hefty razor with a cast head and a long and heavy shaft - a very marked contrast with my 985CL travel razor. It is also an aggressive razor like any slant seems to be; it is not without reason one of the names given to the 39C online is the "sledgehammer". If you have the technique down and keep a light touch, it'll slide straight trough even several days worth of beard with about as much trouble as a combiner harvester have in mowing down a field of hay. It will leave your face significantly smoother than said field though...
The comparison to a hay field is rather apt once you consider how a slant works; it's more akin to the action of a scythe than a knife in that it slices rather than chops - just resist the urge to swipe it over your cheeks.
The 39C is as mentioned aggressive - in fact it is my most aggressive razor so far - and as such I like to pair it with a reasonable mild blade. I have used Feather Hi Stainless blades, and it works wonderfully, but I realised I needed to be very much on the ball when using those - meaning I could either get a wonderful shave or a face full of nicks.
If you're in the marked for a new slant you can't go much wrong with a Merkur 39C in my opinion. If you prefer razors with short handles Merkur also makes the 37C which mates the same head with a shorter, lighter handle.