Sorry for the delayed reply - I was away.
Lowrance makes excellent receivers. In fact, till Garmin started to use Sirf chipset in their newest ones, there was no handheld that IMHO could match Lowrance's reception without using an add on external antenna.
Lowrance's maps are decent but, not updated too often. Still, they may appear to be all that you need but, be prepared to still use paper maps for best detail. Well, the same is true for Garmin. Freedom maps are convenient way to load the maps without the use of computer but, this convenience costs extra. Personally, I rather go for the CD version and loading the maps as I need them. BTW. Garmin maps can also be purchased pre-loaded but, only the more expensive Garmin units can use cards. Now, speaking of price; I suggest that you stretch the budget a bit and get a colour display unit. Colour makes HUGE difference when viewing topo maps. This difference is even more prominent when dealing with relatively small screens that handheld receivers offer.