Having just returned from the 1st screening in Woking, where the original martian landing took place, I have to say I went with the idea that it would probably have brilliant Spielberg effects but that the story would lose something being transferred to modern-day America (just like the 1953 version). But I needn't have worried as the film took me in and I became thoroughly engrossed. I don't actually think it matters if it was in 19th Century London - perhaps HG Wells was just saying that the Martians were far superior than our best technology / weaponry, no matter what time period.
But, on reflection, I have to agree that the ending was a bit of an anti-climax. Maybe it should have shown man's first Mars landing, unless of course that comes after the credits have finished!
Having said that, the ending is only a couple of minutes and I thoroughly recommend the film to anyone.