Many of these "high end" mic pres aren't as expensive as you might think. Buying single-channel units is by far the most expensive way to do it – because you're paying for the power supply every time. Once you get past the cost of the power supply and start adding on more channels – things start to look a little different. Your example was "RNP is around $230 dollars per channel."
API 512C is around $650 dollars per channel
Millennia HV-3D @ $3500 for 8 channels is around $437 per channel
Sebatron vmp-4000e @ $1600 for 4 channels is $400 per channel
Focusrite ISA428 @ $1600 for 4 channels is $400 per channel
Those price-per-channel costs are less than a lot of mid-level pres and channel strips and offer much better performance. People mention the "$1000 barrier" to get into a high-end pre – but that doesn't have to mean $1000 per channel. It just means getting over that hump of buying the power supply and the frame.
In a lot of cases I think the real waste of money is all these mid-level $500 - $700 pres and channel strips. With perhaps the exception of the Grace 101, none of the mid-level units offers much over the good inexpensive units like the M-Audio DMP3, Rane MS 1b, VTB1... and the mid-level units also can't touch the performance of the higher-end units. So what good are they besides adding a few more neato lights in your studio? And frankly, even with the Grace 101 running around $550 – for another $300 you could get into the 4-channel Sytek MPX-4Aii. So even the 101 doesn't escape the "it's not really worth it when you take a good hard look" test.
Since I've been working with Sound Pure I've talked to so many people who have 3-5 or more of these mid-level units. And they keep buying them looking for this "sound" that eludes them. Seems like $500 is sort of an easier target range for people to shell out for a piece of gear. In quite a few cases I've convinced them to sell off their mid-level pres and channel strips and get into a couple of high-end channels. And in every case they've called back or emailed about how gassed they are at the performance difference.
The RNP for 2 channels at $475 is totally acceptable. The Tampa @ $328 is a great deal. The Brick @ $399 is borderline - and it's still delivering mid-level performance, and will give you that nice "whooly" undefined sound if you use it on a lot of tracks.
The RNP, Tampa and 101 all get away with costing much less because of the wallwart power supply – meaning they didn't have to pay the $20K+ for UL approval for an internal power supply. So it's a way to pass on the savings to the end user with a unit that costs less. Fair enough.
And the one interesting thing the RNP has over most of the other units in its price range is that it truly is a "boutique" mic preamp. And it's the "boutique" companies that are turning out the best stuff. If you're looking for a place to invest your hard-earned cash – look into smaller companies that are making their units by hand. One of the very cool things about the internet and pro audio is that it's allowed a lot of small companies to flourish. There's lots of examples of great little companies who never would have had the kind of marketing and advertising budget to even get off the ground who are now well-known because of their name and word about their products getting around on the internet in the various forums. Great River, A Designs, Phoenix Audio, FMR Audio...the list goes on...
If you're a hobbiest and want a couple of channels... running a DMP3 [ $150ish ] through an RNC [ $179ish ] can give great results. Wanna do some vocals and acoustic guitar...the Rane MS 1b [ $150ish ] is outstanding for that. Wanna play with some different colors and versatility... get the VTB1 [ $129ish ]. The Tampa – when you can find it for around $328 – is the only mid-level channel strip I recommend. And the RNP @ $475 and The Brick isn't a total ripoff @ $399. But then there's this loooooong gap... all the way until you hit around $700+ where you can get into the Sebatron vmp1000e. But even at that – why not get the 2-channel Sebatron vmp-2000e for just $300ish more - which is right at about $1000 - and, again, we're at that "magic" number where you start really being able to get into some performance.
If you're a hobbiest and just getting started, don't worry about it. Get one of the inexpensive pres I've recommened here and rock out. They'll do a great job and won't hinder you from making excellent recordings. But if and when you wanna get a little more serious...hang on to your $ – and bypass the mid-level range – and wait until you can crack that $1000 barrier – and from there some serious options open up... A Designs, Hardy, Great River, API...
Once you've got some chops under your belt, there's nothing better than some serious tools. And, yeah, the serious options are worth it.
My 2¢.