You really need to set a budget for this purchase since you can get a very nice laminator, for example, in the $5000 range or you can go to the next level for $15,000. It depends on your intended use and volume. I suspect you are in the $5000 range (I wouldn't recommend anything lower than that and I definitely would not recommend any Chinese import or the Daige), so let me offer the:
Royal Sovereign RSC1400H (Possible older model #, I have not researched the newest model #s)
5 roll holders - paper • media • laminate • liner take-up • media take-up
Heat Assist
Cost effective
Excellent performance
Excellent reliability
Excellent support, warranty, service
Actually, I own this particular laminator and I never use the heat assist for general sign purposes, so depending on your specific needs, you might be able to eliminate the heat assist for some cost savings but the 5 roll holders are of critical importance. Every day I laminate rolls of printed media, which I then take off the laminator and put right into the plotter. Otherwise I'll laminate half to full rolls of media and then take it to the table for cutting, can you imagine that spilling out onto the floor? I would never get a laminator without all 5 of those roll holders.
If you want to go to the next level, I would suggest something like the Seal Pro Series. For the extra $10,000 you get the brand name, supposedly easier roll holders to swap material out with, generally perceived greater value, and possibly higher volume processing. I haven't shopped for a laminator in a long time so these days there may be other good brands and options available too.
The last thing I'd like to say at this moment is that purchasing a laminator is not like purchasing anything else. A laminator may last you many, many years. It is a simple piece of mechanical equipment that will outlast digital printers, etc. Therefore, you should anticipate your future when purchasing a laminator and purchase one that will be size appropriate for you future needs.