If you really want a handheld, the Raymarine RC400 might be your best choice, rather than a Garmin. The Raymarine was I think chosen by Motor Boats Monthly as a Best Buy, and uses Navionics Gold chart cartridges which, in terms of area per £, are cheaper than Garmin Blue Charts. Garmin's cartridges are also proprietary and (as Garmin have already demonstrated with G-charts) can be rendered obselete at their whim.
Personally, I think handheld plotters fall into the "toys" category, as they're far too small to use as serious tools, unless you tend to sail on lots of different boats and just want to take your own plotter with you. Otherwise, for about the same money, you can get a proper 5" screen Navman Tracker which has double the screen area and is big enough to use sensibly.
I looked at the Garmin 276c but plumped for the Raymarine RC400 because I liked the Navionics chart presentation better & the area covered by the Gold XL3 suited my purposes.The RC400 works down below & I run it off the 12v ciggy lead supplied.I also use it in the cockpit off the lead & the batteries,although the batteries do not last very long( they are rechargeables).I do not find the screen size a problem & I like the transportability.I find it suits my needs.I bought mine from Yachtbits & paid circa £447,others are charging £499.The charts are extra.
I paid £490 for a Navman Tracker 5500i at the boat show complete with one large area C-Map cartridge (not the new 3D version). By the way, I have yet to understand why anyone would want a 3D marine chart!?
3D mode is only one optional feature included in the new C-Map MAX charts. Most GPS users are accustomed to the perspective "rolling road" display when navigating to a waypoint, and the option of being able to combine the "rolling road" display with real chart detail seems sensible enough.
Other things I like about the new MAX format are the aerial photos and coastal road mapping of marina/harbour areas, animated tidal arrows and dynamic navaid displays. All simple enough ideas, but they should enhance the usability of the charts.
Unfortunately, it's necessary to buy a new plotter to benefit from the new MAX charts.
I have purchased an RC400, you are correct that when off the external power the batteries run down very quickly. Have you found the backlight timed power off setting - it helps.
There are some questionable vector chart features, for example I don't want to see 6 submarine icons when zoomed into a 1 sq mile section of the Solent. Also why do the charts turn to black and white wire diagrams when zoomed out to a large coastal area that is still within the over 3XL coverage?
Otherwise I think it is an excellent device, very fast and lots of pixels the fine details.
I've used a Garmin 176c for a couple of years and it's much more than a toy.
I chose it because
a. It's a Garmin and I like the logical way their controls work.
b. I do move from boat to boat and it saves trying to learn new systems before you leave harbour.
c. It's powerful enough to support a navigator who isn't solely using electronics.
d. The screens big enough to carry out quite complex pilotage.
e. It can be moved about the boat to suit your needs.
I guess if your used to using a big screen plotter that your comfortable with that a handheld might be seen as constricting. But for a first dabble they are excellent and I doubt if I'll rush to "trade up".
I have the Garmin 276C and bought it for several reasons. I have an old fixed GPS in the boat so liked a handheld with a Li ion battery that is good for 10 hours or a days sailing if needs be. It can be used below and on deck with the same antenna. Tides, marina info, echo sounder display etc. The screen is excellent; big enough I feel if you are using it on a chart table when sailing. All planning can be done in Mapsource with the maps on CD and these can be put onto multiple PCs. The unit connects via usb to upload/download, so you don't need a programmer. I bought the in-car kit for the memory brick and use it for voice directed driving. SWMBO like to hear spanish driving directions! I load 3rd party topography maps and take it skiing. The Garmin online support is excellent and software/firmware upgrading is easy.
What I don't like are the maps are one-off purchases so you have to pay to upgrade and I don't think the Mapsource program is as feature rich as it could be. It would be nice to have a more database type way of storing waypoints and tracks. I guess if I looked into 3rd party software I could find the stuff I want. You end up putting a lot of your cash Mr Garmins way.
All in all a good compromise for the different functions; wouldn't want a portable unit any bigger or heavier.