I had heard that some inverter designs work better with different solar panels. One example givien was the Fronius inverter were a better choice when using Evergreen panels. Does this sound reasonable, or ...?
If so, what factors affect matching the inverters to panels?

No, any panel with any inverter, buy the panels on price, buy the inverter based on what the forum regulars suggest.

My preference is the Xantrex GT series, they have the best efficency, lowest cost per watt and come standard with full communitcaions and monitoring software. Unlike the Fronius, its a seal design, the Fronius is fan cooled

Evergreen's are nice panels, I just installed a 5kw array on my roof ( the modules are seconds ) with a Xantrex GT5.0 and its peforming very well

I had been leaning towards Sunnyboy - From what I could see, I wouldn't go wrong with Xantrex, Fronius, or Sunnyboy. However, I didn't like the Sonnyboys weight, or Fronius's open to the dust and environment.

From what I could see, it looks like everyone has their own preferences - is my "take" reasonable?

I've only had the GT 3.8 and it has been fine for just over a year now.
raintight fanless

What inverter are you buying and why?

I looked at the Xantec GT's again - hadn't noticed it was a true sine wave - This was one of the reasons I had ruled out Fronius and wanted to go with Sunnyboy. I like the reduced weight - any downside to the Xantrex as compared with the Sunnyboy?
I had read a suggestion to use two smaller inverters rather than one larger one. Cost difference isn't significant between the two approaches. I looked at using two GT2.8's. I could see benefits - among them, less heat generated inside each inverter, and better heat removal - since the cases appear to be the same as the GT5's, the I'm guessing the heat sinks are identical - and would have a smaller heat load.
Don't like needing more wall space.
I'm planning on using 24 Evergreen (180 or 190) panels mounted on two WattSun trackers. Any problem with two GT2.8's - each being fed by 12 panels? Inverter efficiency at lower power levels?

GT5.0's rock, I have a pair ... the heat sink is longer that all the other GT types but the box is the same size. It regulary is running 95-96% on my arrays

I'm a power electronics engineer and know how all of these different units are built, the GT is best of breed, no bull and uses the very best power electronics inside.

There is nothing wrong with having a pair of inverters, but it cost more, its more complex to monitor and with a 10 year standard warranty, I don't really see any benifit of the redunace of have two vs one inverter

Use the sizing chart on the xantrex site to be sure, but off hand, I'm pretty sure two strings of 12 evergreens will work fine. I have on one of my GT5.0's two strings of 15 ( 170 watt ) evergreens from SunElec, it outperforms the larger photowatt arrays.