I have a 2004 Horizon (also Aluminium) and think it's great. Still haven't given her a name. Suggestions please.
Horizons have their fair share of knockers (ooh err) but I think they're great value for money.
Sure, I've spent a little bit of cash upgrading (Brooks B17 saddle, SPD pedals, new bottom bracket after 3,000 miles, new rear cassette & chain after 5,000, new gear cable after 5,000, new bar tape after 5,500) but think that pound-fer-pound they're very good value.
The brake-lever shifters are splendid (still can't get my head around why Galaxy people like bar-ends) and never had any probs (touch wood), and it can take decent camping tour loads. I don't worry about rust like steel bike owners would, but concede that if the frame broke in Timbuktu I wouldn't be able to get it welded. But I'll live with that as I mainly ride in the first world.
Not to criticise people who spend 4 figures on a bike, as I envy them massively, but I reckon the Horizon is an excellent "entry-level" choice and will get you on the road enjoying life just a much as someone on a Koga Miyata or Super Duper Schmooper Ultra Schmultra Galaxy.
Enjoy!