Here is a partial listing of the features NOT present in the c3x0 series that ARE in many car navigator units and especially in the StreetPilot 2610/2620 units.

1) You cannot set destination waypoints (except for Home) directly.  You can input addresses and store these in your FAVORITES list.
2) There are no user adjustable data fields such as speed, distance, etc.  What you see in the review photos are what you get.
3) When you power up, you do not go automatically to the map screen without pushing a touchscreen button.
4) There is no way to store tracks, routes, or waypoints,  Just your favorite addresses as noted above.
5) There is no readout of longitude/latitude available.
6) There is no altitude readout.
7) There is no satellite display page.  There is an "indication" that 1,2,3,4,5(or more) satellites are locked.
8) The only datum available is WGS-84 (not that unusual for car navigators).
9) The  smallest "map chunk" you can load in the C320 using the furnished CS6 maps is one state.  You cannot load a part of a state.
10) There is no "pop up" window to show turn details as you approach an intersection.  (There IS a pop up guidance window, but you must press the SPEED/Distance to Go display while in a route to view it.  You can also view the coming turns in a route by further pressing the down arrow on this pop-up window.) 
Instead of the pop-up window, for normal turn guidance, the c3x0 units place a large arrow on the map showing the proposed turn.  Note:  I find this somewhat less than satisfying as the display of the OTHER streets, ramps, cross streets, cloverleaf roads, etc are intentionally "washed out" so that they have very low contrast relative to the route which is quite readable.  This (for me) makes determining exactly where to go a bit tedius on complex road interchanges.
11) If two turns are closer together than about 200 feet, the unit fails, much of the time, to annunciate the second turn by voice.
12) You cannot upload tracks to your computer as tracks are not stored.
13) You cannot view the trip computer unless you are running an active route. (Press the ARRIVAL TIME readout to view the trip computer screen.)
14) There are just a few options in the various setup features.  (See screen images.)
15) The unit has a simulator mode but you have to wait for the GPS to try and lock and then time out to use it.
16) VIAs are not supported.  That is, you cannot direct the unit to take you from address A to address C by way of address  B.
17) There are no options for route calculations such as "quick, good, better, best" in the c3x0.  Route calculations are very fast (Much faster than the SP2610) but I have often seen the c320 take out-of-the-way loops and other short "excursions" that the SP2610 did not suggest taking.   None of these was serious, just unexpected and inefficient.
18)  When you tell the c320 to take a "detour" it can take you pretty wildly out of your way, but it eventually gets you there.  The SP2610 detour routes make more sense.  I have seen it (on a just a few occasions) take a 5 mile detour route when just making a U turn would get you where you to the new route in just a mile.  I suspect this is a result of the routing algorithm not taking time to check available alternative routes.
19) When making a "detour" on the simulator, I notice that the machine asks if you want to simulate the route.  If you happen to be going SOUTH and want to detour, the simulator has no problem immediately asking you to go in the NORTH direction which can be hard to do on a limited access highway.  I will try this out in a real situation and report further.
20) There is no GPS estimated accuracy readout.  (Not that one is needed on a car navigator that does not present lon/lat position.)
21) There is no Sunrise/Sunset display as on a SP2610/2620.
22) AutoZoom cannot be turned off in a route since this is essential for turn guidance if you do not have pop up windows to annunciate turns.
23) Applies to c320 only:  You are not able to route to cities or to intersections on the basemap.  You can route ACROSS the basemap between two "detailed map islands".  It is possible to "pan" across the basemap and then to route to a point that you pick out but this is pretty tedious.

Please do not read the above and think that these are ESSENTIAL to a properly functioning GPS Car Navigator.  MANY OEM and competitive units are limited in more areas than these.  This list is meant to convey to experienced GPS users that the c320/c330 series are truly BEGINNER's car navigators and as such does NOT have some  features that many have come to expect in Garmin and other "full featured" car navigators such as the StreetPilot 2610/2620.

RETURN to C320/C330 review.