I have had experience with several types of cell counters.  The accuracy of these instruments is probably on par with what you are going to get manually counting chambers; the main appeal of these is the convenience.  The main downside is the expense. 

The Countess from Invitrogen uses slides that require loading 10 uL in each side (20 uL for the whole slide) of cell solution.  The Countess is self-contained so you do not need an additional computer, but it has limited memory and you have to purge the data every so often; otherwise it cannot function effectively.  It is also not the most durable instrument I have ever seen. 

The Cellometer from Nexcelom requires a separate computer but it has more functions than the Countess and data storage limits are only limited by what the computer can hold.  Cellometer slides and Countess slides are pricey. 

So are the "sensors" that go with the Scepter from Millipore.  The Scepter has the smallest profile, since it is handheld, and it is probably the most convenient to use; it too has limited data storage.  It also requires a minimum volume of 100 uL of cells for counting, and there are two different sensor types depending on the range of cell concentrations, and the Scepter, which is charged like a cell phone, can lose charge pretty rapidly.

Among the three, I would choose the Cellometer because of the options available for doing counts and the data capacity.  The Scepter is smallest and easiest to use but has numerous disadvantages.  The Countess is serviceable but Invitrogen's record with equipment durability and accuracy is questionable.  No matter what you choose, there will be expense in buying the slides/sensors for doing the counts, so they really only make sense for a large volume of cell counting to avoid the hassle of manual counting.

I hope this is helpful.

Go for Beckman Coulter vi cell-XR. It tells you how many cells are being counted each time, viability etc. Its at par with manual counting and it makes your life so easy.

I worked with Countess from Invitrogen and i was very satisfied from it. they now have a reusable slides and even florescence readout but I didn't work with this new model

. 

Logos Biosystems provides series of cell counters: http://www.logosbio.com/

Hi Kristina,

some specs for CASY:

ideal measuring range for CASY is approx 4,000 - 10,000 cells/run to ensure statistically relevant data. The accuracy and repeatability is +/- 2%. Dynamic range is 1:40 in diameter and 1:70,000 in volume. Size distribution resolution is typically 0.2 µm. 

Compared to manual counting? Well, it's much better reproducibility, counting is independent of user, day, even instrument or lab  - and it delivers additionally viability data, aggregation data, biomass, cell debris and cell volume. 

If you'd like to find out more, follow the link below. 

Best regards, Ralf

http://cellcounting.de/casy-kennenlernen/?lang=en

Dear Ralf,

Thank you for this information. Do you know if this cell counter has been validated for use within a GLP setting?

Best regards,

Kristina

Hello Kristina,

indeed this cell counter is GLP/GMP compliant, CASY TTC even is 21 CFR Part 11 compatible ( two "flavors" exist, CASY TT and CASY TTC).

Below you'll find all specs: 

http://www.ols-bio.de/en/cell-counting/

The NC-200; 3% variance; Low Maintanence; Pre Mixed

Please also consider the repair costs... I have been using CASY cell counter in different institutes and both broke down a few times during my stay. Repair was ridiculously expensive. For minimal repair (change of tubings) they charged 2000€ (around the price of a new image/slide based machine)! I do some electronics on the side and I think the display used isn't also very high quality either. It tends to suck air bubbles, which is sometimes hard to get rid off!