Dental implants, when done well, are designed to look and feel and function just like the natural teeth they are replacing.
Dental implants will never decay, however, gum disease around the dental implant may still occur with neglect, just like in the case of natural teeth.
There is absolutely no issue with eating normally with dental implants!
Having said that, I have seen cases gone wrong whereby dental implants were not placed in a good position and alignment. This may give rise to long term problems in terms of the stability and balance of your bite.
The skill and experience of the dental surgeon is probably the most important factor in achieving a good predictable result.