That's a good question - asked that myself multiple times, too. For now I flashed all my LB4Ms with the routing firmware just to have the L3 features available if they are needed (exactly as you describe your situation). Haven't found any show-stopper, yet. But to be honest: never did a peformance comparison of the different firmware versions and I don't use the WebUI. The only facts I have for you:
- has more features than all other firmware versions
- it's the oldest firmware (potentially more bugs / security flaws?)
- some commands differ (slightly) between the firmware versions (that's annoying if you have a config and want to switch to a other firmware version)
Please let me know if you find something that keeps you away from the routing fw.
Thanks so much for the detailed answer, aj. That's great.
I actually didn't pick up on the fact that the routing firmware is older than all the others - I thought it was around the same as 18.104.22.168. That's definitely a shame and could lead to reasons why it might not be preferred.
It's a shame the latest firmware is the one that has neither routing nor Web UI. I suppose people are saying the UI is pretty awful, but it's something I, as someone very rusty/ignorant on switching config (the last time I can remember using Cisco-style commands was about 2005 I think), would find quite useful to see what options are available and configure them the easy way, then hopefully learn from the generated config.
But I think I'll have a go with the routing at least to start with. My needs are so minimal that I can't imagine it could be slower in a way I'd notice - if it couldn't manage 1GB/s on 6 - 8 ports out of the 48 then it would be downright broken.
Your third point was the sort of thing I was most worried about - like how the switch didn't even work out-of-the-box with the routing firmware, forcing me to ask for help. If I found it was constantly a struggle to do anything basic because everything was more complicated to get running right and/or the commands I Googled and found in this thread didn't immediately work, that would definitely be a reason to go back to a simpler firmware.
But hopefully the UI can help me out most of the time, and again as I'm not likely to do much advanced stuff, I'll probably not even notice the difference until such time that I have a go at some L3 routing. Which will mostly just be for the fun of it and experience/learning - I expect I'll have to invent reasons to use advanced stuff like that in my home network!
Thanks again for all your help, much appreciated.