So I bought a Nikon D5000 with the stock kit lens (18-55 VR) last summer.

I'd like to get a longer lens for it, but in order to avoid dragging tons of kit about with me I'd like a "one lens does everything" effort, so looking at superzooms, like the Nikon 18-200 VR or the Tamron 18-270. Use will be general biking & travel stuff.

Having read the reviews, they all seem to be limited in an assortment of ways – soft, distortion, AF lock on issues etc. Real world how much of an issue is this? Lens speed all seems much of a muchness (f3.5-5.6ish) – again likely to cause any issues in typical UK conditions? All the f2.8 zooms seem to be quite limited in range and terrifyingly expenive.

I'm currently leaning towards the Nikon (more reliable AF), but is there anything I'm missing? What's reliability like? I've seen some used ones available, but they're still bloody expensive.

I'm by no means an expert photographer, but I've tinkered with cameras in one form another for agaes, so have a passable understanding of what's going on.

Thanks!

Jon

large-range zooms seem to have softness issues IME, making them usable only over a smaller range anyway. Could just be the way I use them and the fact that I can't afford top-end lenses though.

While the 18-200 VR lens is a 'do it all' lens, it's still a pretty hefty lens to be lugging around all the time.
You'll be wanting to try it before you buy it.

I've got an 18-135 on my D80 & even that feels pretty big when out & about, especially if I take it with me on the bike & it's loads lighter than the 18-200 VR.

I'd keep the 18-55 & get the 70-300 VR as a second lens. It's a good lens. It can hunt about a bit sometimes, but this is generally in dull conditions when the contrast is low. Or sell the 18-55VR and get the 18-135 or 18-105VR instead, if you really want one lens that will give you more reach.