Here are the settings I use personally. They combine Cnet's sort of borky calibrated settings with OCD-levels of eye-balling:
Yes, it has relatively low input lag with "Game" or "PC" mode while still looking good, even on composite with 480i and 240p signals. This TV was even recommended by www.displaylag.com specifically for gaming under "For Gamers On A Budget":
Not only that, but this TV has a "native" option for displaying an HDMI video signal without any overscan, which is good for making sure nothing on the in-game HUD is cut off.
Lastly, this TV even has a VGA input (up to 1366x768 and 1280x1024 without manual EDID override) which can be useful for a DreamCast or an older Xbox 360 without HDMI, especially if you're already using the composite input for something since that uses the same physical plug as component on this TV.
I would try the following: Push "Menu" button on remote and highlight "Installation" on TV menu and push enter on remote. Then, on the "Installation" menu shown on the TV hightlight "Store/Home Mode" and make sure the TV is set to "Home".
From what I can tell the differences are as follows: 2300u has a refresh rate of 60Hz is a smart tv and has 1 HDMI port. The 350u has a refresh rate of 12Hz is not a smart tv and has 3HDMI ports.
The 350 has a slightly better user rating than the 2300u. Hope this helps.