I've got a homemade job in the house, a DX torch and the Seca...to be honest the DX is the best option if money is even the slightest issue - the torch is better than the bikelight as the batteries are cheap and you can buy plenty - full beam gets about 1hr 10mins of light but if you don't use full beam you can get almost 2 hours per battery...when that starts going, plug a new one in...I've got 6 so have almost 12 hours with that.
My homemade job was inspired by robdeanhove's original thread and it still chucks out about 4hr 30mins of light.
The Seca - I didn't pay for - has the best light pattern BUT this idea of not enough light? It's too much light in my opinion. Not sure why people need everything to be white flared to go biking...
The Ay-ups I think have more than enough light output to go mental fast offroad at night...really not understanding why people are saying they aren't bright enough.
I've tried a couple of Exposure lights and I've had a mixed reaction to them...the 3 LED main unit (forget the model name) seemed to be very good but I didn't get the same sort of performance from the Diablo (Diabolus?), I think that uses 3 LEDs but the uprated ones...I just didn't find the beam and light to be as usable for some reason.
Comes down to 2 types of night riders I guess - those that ride at night because they can only ride then and there are those that ride at night because it adds to the challenge. I think the latter don't like daylight brightness and I fall into that group.
Each to their own, if you have the cash then there are loads of options...you asked about the Seca so I gave my opinion of them - very good lights - far too bright on the highest setting and stupidly expensive if you pay full price and the battery is a bit hefty but a very good system with very usable light beam.
The others were just my opinions on them.