I'd been pondering this decision for ages but finally went for a Satmap and I've been very happy with my purchase.
The others I considered were the Oregon 400/450, Dakota 20, Memory Map Adventurer and the new Lowrance Endura.
I decided against the Endura as new GPS systems always seem to suffer software bugs and I don't fancy being let down. It was only launched this week so there are bound to be teething problems.
The Memory Map unit gets some pretty poor user reviews due to software and hardware problems so got ruled out early on.
The Satmap unit is incredibly easy to operate and has an excellent bike mount. Maps aren't the cheapest but I managed to get the North of England and Scottish lowlands/borders 1:50k maps for £70 for the 2. I always carry a 1:25k OS map still so if I'm not 100% sure I can use the 10 digit grid reference from the Satmap to double check. I will probably invest in the 1:25k maps for my local area at some point but the 1:50k is fine 95% of the time.