The only reason I was trying to keep the first router's firmware the same is that it was a bitch to configure it for a wireless printer server. The process ended up in a call to Linksys support. I didn't want to mess with that again. But that printserver is in the same room my stuff would be going into, so I could just hook the printer up to my PC instead, and make it a network printer from there.
I understand this completely. I hate wireless printers and print servers. I refuse to deal with them entirely. For printing, I highly recommend sticking to IEEE1284, USB, or regular Ethernet.
Of course if either of these linksys routers doesn't support custom firmware, then all bets are off.
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Edit: The Tomato 7z file seems to have versions across the board for the routers. The webpage interface for this router identifies it only as WRT54G. I assume the firmware revision doesn't matter, only the hardware version, which I don't see here. I'll examine the unit itself sometime.
I know for sure that DD-WRT and Tomato both work on WRT54G's up to version 4.0 and the WRT54GL (which is basically a WRT54G v4.0). I think the WRT54G is on like v8.2 now. After v4.0, Linksys reduced the size of the RAM and flash RAM to make the WRT54G cheaper to manufacture. Suddenly, DD-WRT wouldn't fit on it anymore. I think the DD-WRT project has released support for later hardware revisions, just with a reduced feature set. They have also expanded support to a ton of other routers, mostly those that are Broadcom-based. There is DD-WRT firmware for Linksys' new simultaneous dual-band, gigabit WRT610N v2.0.
Tomato only supports the WRT54G, the WRT54GL, and some Buffalo one (WHR-something). For the WRT54G, I'm not sure if Tomato supports anything beyond v4.0.
DD-WRT has a much broader feature set than Tomato, but I found that Tomato's QoS works a lot better, at least compared to DD-WRT v23 SP2. I also liked the monitoring and reporting features of Tomato better. I've never tried v24, so I can't comment on it at all. Tomato does everything I need it to do, and seems to do it pretty well. I have no need for creating a public hotspot that has an authentication webpage, or having my router double as a VPN concentrator or anything like that.
Edit: I just looked and saw I was wrong about Tomato's hardware support. It's a bit broader than I stated, but still not close to DD-WRT's supported hardware list. But yes it looks like Tomato only supports WRT54G up to v4.0.