I've got the 55-300. I paid about £160 for it from one of the greys. It's a good enough lens, but?
I think that the 18-200, especially 2nd hand is FAR better VFM. You ought to be able to pick one up for around £80 2nd hand and if you hunt, for perhaps as little as £100 'un-used' split from a kit when buyer has opted for the 300 instead.
And the reach it 'lacks' is probably an actual advantage to many!
200mm on a crop sensor camera has the effective 'reach' of a 300 on film/full-frame. Before diving into Digital, a 70-210 (equiv of 46-180 on APS-C Digi) was a favourite 'general purpose' long zoom; and that's exactly what I used for best part of quarter of a century, and rarely found many situations I wished I had more... I DID find'em, and for them, I popped a 3x tele converter behind it, to take me from 210 to 630, pushing the sort of reach serious birders & the like got from big mirror lenses (500-1000mm)...
I didn't do it very often! Long lenses often make more problems than they solve, and the first one they make is actually finding your bludy subject and keeping it in the friggin' frame!
Seeing such a small portion of a scene, you can spend half your time scanning back-and forth to try and find whatever it was you wanted to see more closely! Then when you find it, even if its planted solid on the floor and never going to move, tiniest movement in the camera, swings you half across the landscape! And being long and being heavy, they ent exactly 'easy' to hold still!
So, you need higher shutter speeds to avoid camera shake, but they tend to have less useful maximum apertures, especially at the long end, begging slower shutter speeds and higher ISO's.. and so the problems start to compound....
Digital, 'sort' of offers some compensation; dial an ISO up to what, 12,000 or more, and change it frame by frame, is an astounding boon over film, that we were lucky to get much over 800ASA, and were stick with for a full 36 shots; and these electric lenses have curious 'stabilisation' systems, 'supposed' (I'm not entirely connived by them) to help hold the lens a bit steadier, even if we cant.. BUT, you still have to find the dang subject and hold it in the frame, and half the problems are still there!
NOT having that added reach, means you don't have these problems.. you ONLY have the one problem... the subject, which you can actually find and can actually keep in the frame... is just a bit small!
So back to basics, make the composition work for you; fame wide, or zoom with your feet and find a better angle! Might actually find 'better' photo's that way.. and if you don't? Well, good chance while you may be a bit disappointed your subjects a bit small... you'll be less disappointed than them not being in the frame at all, or so blurred you cant tell what they are!
My 'hope' when I got the 55-300, was that with an 'equivalent' range to 80-450 on 35mm film, it would offer 'almost' what my 70-210 did, with 3x converter. Given that I rarely used the converter, and when I did, anything much beyond 450 magnified the problems as much as the subject and was almost un-usable and so unused anyway; It would cover the 'practical' range of that combi, without resorting to a converter..
Reality has been... well, yeah... it HAS... b-u-t.. was it worth it?
In almost three years, apart from a couple of tripod mounted moon-shoots for my daughter, its hardily ever been racked much beyond 150. Couple of events that have had me 'hopping' between 18-55 and 55-300, have actually made me wonder whether I'd not be better off chopping the 55-300 in against an 18-140 or 18-160 super-zoom, and that begs notion that I'd be as well up leaving the DLR at home and using the O/H's little mega zoom 'bridge' thing, that was cheaper than any of the DSLR lenses!
Which, all raises more questions than it answers... BUT, that 'cheap' 55-200 is half the cost; could be more than 'enough' to find out what you do use, and if you need more, and esp if you buy 2nd hand, better inform decision where to go from there.. money may be better spend, ultimately on a 'better' 70-300, or if you are regularly regretting lack of reach something more dedicated the long range; if not used so much, then one of the 18-1X0 super-zooms could be a better compromise; and if just an 'occasional' lens, then the 55-200, could be just enough, to not feel you have spent a lot of money on something seldom used.
For the Tamron, I have one and its a great lens, the VC is amazing.