If you can try before you buy, that would best.
The woodworking show this weekend at Ally Pally would be a good start as, hopefully there would be several to try, if of course you are near enough to get there.
As far as which one?, a lot depends on what use you are going to put it to.
I would go for a quality make, 1/2" (also comes with 1/4" collet) at least 1500w upwards, If you bought a quality 1/2" router as apposed to a quality super expensive router, you could also budget in a quality small trimming router.
Thus you would have one for heavy work and one for light work.
I know that's easy enough my those of us who has several, (I have 8 but that's over a great number of years)
But IMHO you do do need at least two, one for small stuff, the other as big as can get for heavy stuff.
My main Routers are the Big Triton in the table. for big hand held stuff A 1700w Bosch, 2050w trend. for small stuff I use the small Bosch pof 500 I also use A small ferm, cheap but useful.
The others are for different purposes, EG I fit my Stanly to my RAS.
John. B