Hi etarran - good questions. Firstly, with the FPVLR antenna's, yes I was happy with them and didn't experience anything too bad in regards to signal over the distances that I fly out to. My only 'gripe' with them is the connection. When screwed down, the antenna is not firm and can move about (spin) on the mount. No big problem as a little section of heat shrink over the sma fixed that.
The main reason I went to the Itelite design was for two things. Firstly, it allowed me to bring the additional 2.4 antenna out of the ST16 and secondly, the reports on the signal strength were very good. My only 'gripe' so far is that I couldn't be bothered removing the Itelite unit each time I fly so it won't fit in my case. Problem easily solved by purchasing a smaller case that now houses the ST16 with the Itelite.
In hindsight, I am happy that I have tried both and I am also happy that I have settled with the Itelite system. Also, if you want to maximise your signal strength and consistency, then I would also recommend the antenna upgrade to the YTH as well.
Keep in mind that, to maximise the effectiveness of the Itelite antenna, it needs to be pointed towards the H.
PS: if you are interested in the FPVLR antenna's instead, send me a PM. I'll send them to you as long as you cover postage. I have no need for them.