The TC20 from Bio-Rad is very decent in my opinion. It's simple, counts are reliable (for PBMCs at least), it does discriminate dead cells based on Trypan blue staining (or other dyes as well probably) and - this is also important - counting slides are not dreadfully expensive. The automated counting process is slightly quicker than when doing so manually, but most importantly it is waaaay more comfortable when you have to count many samples (and you can somehow do something in parallel). P.S. I am not working for the company I mentioned.

Hi Julien, I've tried the TC20 but the problem was that it als counted debri as dead cells. And there was some discrepancy between the manual counts and machine counts

Really ? I am surprized because this device has been very satisfying for us and manual and automated counts were very similar each time we checked. Are you sure that the device has been optimally calibrated for PBMCs and that there is a propper threshold for size so that only cells, and not debris, are taken into account ? Another explanation could be the presence of debris within the Trypan blue dye that would confuse the device (and in this case this would be solved by filtering). But I guess you checked all this.