They are by far the most reliable and long lasting sytem I have seen. Not as flash as some, but good, well made stuff which can be serviced, added to and supported by a manufacturer here in the UK.
For £125 you can get a NiMH battery, a single Halogen lamp and a basic charger.
The 'basic charger' only means you have to remember when to take it 'off charge'. I have the smart charger because I am not, and don't want to cook my power pack.
As long as a second lamp can be added to the single light system, I think you can't beat it for the money. Even the best of everything only pushes the price to £169 for the halogen system.
If any other system includes NiCad or even Lead Acid batteries, you really are compromising things. We found a set of lumicycles were one of the greatest extensions to our cycling. Not only is off roading at night fantastic, but they are great for use training on roads at night as well. Both our sets are over five years old with only new bulbs being necessary (Cheap in DIY stores).
Many riders in our night riding mtb group tried the cheaper options, but all have ended up buying Lumicycles.
I've had a set of Smart lights for quite a few years now and never had any problems with them. The set I've got has got an old fashioned lead-acid battery which is quite heavy, but you can get a Nimh powered one for about 80 quid;
IMHO, nothing beats Lumicycle and in the longer term it is worth shelling out the extra cash for one of their longer-lasting batteries and a couple of different lights. I run one of their 15 LED lights with a 12W Mid (between a spot and a flood) up front, and that's perfectly good for night-riding. With this setup I can get 6 hours out of the (long life) battery before needing to recharge. The great thing about Lumicycle is that they are so simple that you can switch around different bulbs really easily...