Just wanted to share my thoughts on the Retrotink 2X.
It's an alternative to your flatscreen's built in upscaler or $20 external upscalers that add a lot of lag by over-processing the image from standard resolution sources. It also doesn't add lag like the OSSC and Framemeister.
The Retrotink accepts component, S-video, and composite, and has a fast onboard chip that simply doubles the line output (hence 2X) from 240p (also 480i, with caveats, seen below) sources to 480p while converting to a digital HDMI signal, basically ensuring that most HD televisions won't further process the resulting image.
For me, it reduced input lag to the point where it's almost as responsive as playing on a CRT. I was able to test this directly with my LCD modded NES lightgun ROMS. For those not sensitive to input lag, this may not be an overtly beneficial feature.
Apparently, for image quality, the Retrotink shines brightest with component cables. I'm using composite cables exclusively through an 8 port switcher. I have noticed an improvement in both sharpness and contrast across 240p consoles, particularly with my N64, which looked like hot garbage through the composite inputs on my 1080p TV.
I suppose in the future I could pick up some component cables for my SNES, Genesis, and maybe even N64 (HD Retrovision perhaps?), but I doubt I'll RGB mod my NES. This is a particularly big deal for me because my TV doesn't accept a 240p signal over component, so the Retrotink 2X should enable using aftermarket component cables, which is cool.
So far, I absolutely love this thing and it was worth the money, even if I never invest in component or S-video options.
Some minor issues:
The Retrotink uses a mini HDMI. For most people, you're going to have to buy an adaptor or a cable that goes from mini to standard sized HDMI.
No power supply included (microUSB).
It boots up into component mode with 2X scaling every time. Since I'm using composite, I'll need to keep the Retrotink running 24/7 or face having to press the inconveniently-placed mode button twice every time I want to play an old console. I was hoping to be able to plug the micro USB into my TV port, but that makes the Retrotink shut down every time I turn off the TV. That means that my 7-year-old son won't be able to play Super Nintendo without help.
Similarly, using multiple sources, such as S-video and component, will force users to find and press the little inconvenient button frequently. Some kind of input detection software would have been amazing, but this thing isn't meant to be loaded with features. It also is recommended not to have multiple powered devices plugged into the different inputs on the Retrotink at the same time.
With 480i sources, such as PS2 or Gamecube, picture quality might be worse through the Retrotink than through your HD TV's standard inputs (de-interlace may cause flicker, combing), although you should still have less input lag. *Edit* I have a PS2 hooked up to the Retrotink using composite cables and haven't noticed any glaring issues yet.
Finally, the unit is a little on the pricey side for what it's doing (about $108 shipped). However, it is one guy who developed this ingenious device for an extremely niche market, so I can understand that he's not getting any kind of volume discount.
It's also a bit dicey ordering one of these. Resellers like Castlemania sell out quickly. I ordered directly from Mike Chi, the creator, at the Retrotink website. The website doesn't give you a reliable time frame for delivery after ordering. Basically, you get a receipt from PayPal and then it's just radio silence until you get a shipping notification. You can follow him on Twitter, but he doesn't talk much about shipping stuff out or inventory. He shipped from San Diego and used the USPS with tracking. It took nearly 2 weeks from ordering for me to have the product in hand.
*Edit* I forgot to mention that I have noticed crackling audio from certain sound effects on the N64 (rolling boulders in Hazy Maze Mario 64). It's been a minor distraction so far. I'll keep testing, though.