What is the difference between the RE and GTE models? Is it simply the double handle or what?

Also are they good enough for long distance stuff...they aren't that much in size compared to the 1000XTE are they?

AS far as I am aware the differences between the RE & the GTE are
1) Double handle on the GTE
2) Metal rimmed Spool on the GTE
3) 3 Extra Ball bearings on the GTE

As for line capacity, I believe the 8000 GTE / RE Holds 320 yards of 12LB line
and the 10000 XTE holds 420 yards. I have both these reels and to be honest I can't see very much difference in hight of both spools, the 10000 XTE has a slightly deeper spool hence more line capacity and the spool is all metal but as for casting distance I havent noticed any major difference between what I get with both reels. (I am not the worlds best caster tho!!)

I used the 8010 for distance for a week's session in France on a silty water and subsequently bought Emblems.

Although the actual distance cast is not THAT much difference (I'm no great caster, either), After a week of dragging a decent size lead in from over 100 yards through silt, several times a day, the 8010 was (and still does) making some very strange noises from the internal gearing. If you do anything like distance work, you will soon appreciate the extra cranking power with the big spool reels.