My vote is for the Acewell 4354 series. For a bit more than the 28xx series you get a lot more guage (needle tach, variable back lighting color, ability to input starting mileage, plus much more). I ordered mine from acewell.de to get the right version and better prices...
You can get the speedo cable to be plug-n-play but as stated you must rewire or incorporate the wiring that comes with the new gauge.
I'm in the process of my own install right now. I bought a plug and new pins and rewired the gauge plugs to work with Triumph's plugs.
All is working now, just have to fabricate my mounting bracket.
See this post
for pics of my install so far.