Dear Jean-Marie, 
     unfortunately I do not remember what is a PTI TimeMasterT and PTI does 
not provide enough information on their website. I am not sure that is a wide-
field FLIM, but do correct me if I am wrong.

WF vs LSM: as for other techniques the answer relies in the applications you 
wish to pursue. If speed (and perhaps costs) is an issue, wide field FLIMs are 
usually very useful (Lambert Instruments, LaVision / LaVision biotek, ...). 
Although there is not yet a single-shot wide-field FLIM commercially available, 
you can get images in 1-5s typically. Speeds up to 100Hz have been 
demonstrated, but I would say that commercial systems will be not able to 
achieve that. This will soon change, but currently this is the situation.

There is a WF TCSPC available from EuroPhoton GmbH, perfect for precise 
measurements, but only at low count rates.

LaVision Biotek has also a good option with their TriM Scope, a multi foci TPM 
that can be coupled with wide-field FLIM detectors.

Finally, laser scanning systems. Often they offer data of better quality, 
resolution and contrast, but you get images with acquisition times >10s, 
typically in the 1-5min range and sometimes longer if you purchase a MCP-PMT.

Personally, I have been very happy with either wide-field or laser scanning 
FLIM systems. Which are the typical experiments you wished to implement?

Regarding the upgrade of the LSM510NLO/MaiTai to FLIM, that is a perfectly 
reasonable/feasible solution. It is cost-effective (it would not be if you had to 
purchase the confocal and Ti:Sapphire laser!) and you have commercial 
solutions available (B&H, picoQuant, ISS and Nikon, ...). 

No commercial interest in the systems mentioned, and I have certainly 
forgotten some companies!

Cheers 

Alessandro

www.quantitative-microscopy.org
www.wikiscope.org
www.hutchison-mrc.cam.ac.uk