I'm using UHU plastic glue... a 30g bottle with a fine precision-needle to apply the glue.
It's probably exactly the same as Revell plastic Glue with the precision needle, but I got this bottle for free from an modeltrain-hobbyist who could take his hobby with him while moving to another country...
I'm pretty satisfied with the bottle... A little disadvantage is that after applying the glue, the needle easily keeps leaking a fine drop (probably still some pressure in the bottle because of me squeezing a bit too hard)...
Years ago I used Revell plastic glue in a bottle with brush-dop... but because of me being to clumsy I spilled many of those bottles allover my desk (lack of coordination to put the brush into the bottle again :s ).
But actually, most of the time I just use a superglue (CRC Quick Fix) which works for just anything...
In general, for most glues, it's just the name you pay for...
Superglue is superglue, no matter what brand it is, they're all about the same (just breath on your parts before sticking them together, the extra moisture (waterdamp) of your breath makes it stick much faster, and a small amount of water is needed to start the superglue-reaction of every brand of superglue).
Most plastic glues (such as GW, Revell, UHU, ...) contain butylacetate (which is the component that causes the smell of these glues). It's one of the basic solvents to make the (most) plastic parts "melt" on eachother...
Because of this melting, it's sometimes not even necessary to fill gaps with greenstuff (if you're lucky)