I think the trade-in offer is tempting, especially for anyone who already owns Satmap proprietary map cards that suit them. Any accessories, like the bike mount, the LiPo caddy, screen protectors / Proshield silicon cover (itself on offer at the mo' for £20) and so on, can be retained as the case itself is identical across both models.
Their in-house online map tool, Xpedition 2, is much more practical than the old, Silverlight based, Xped. mk1, although in typical Satmap style, is slightly undeveloped and not without its frustrations!