Others say...

"useless, falsely advertised junk"
One of the worst products I've ever purchased. The top isn't secure so that it leaks; so much for travel.

"Just get the cone"
The good points: the blue color is as gorgeous as it looks in the picture. The metal interior keeps beverages warmer longer. The sip hole is closeable, but not leak-proof. The cone method is awesome for someone who only drinks one cup at a time and doesn't want to fuss with a coffee-maker.
The bad points: within twenty days of receiving the mug, the lid's seal was leaking and dribbling in two places from merely one use or less a day. The bottom of the mug was not cut flat and wobbles dangerously, making gentle stirring a two-handed production. Calling for help was a bear because of different customer service companies handling different Melitta products. The manufacturer refused to replace it because it was purchased online.
To sum up: get the cone alone for a cheaper price either online or at the store. I use it with another commuter mug daily and love it. The Melitta mug is junk.

"Ready Set (fix lid) Go"
I like the coffee making part of the coffeemaker, but, like many reviewers have said, the lid is VERY loose. If the lid is on right, you can drink from it without dribbling down your chin, but it doesn't take much to knock the lid off of the cup. The cup itself looks good, and fits in my car cup-holder (a big plus, compared to those that have handles that get in the way).

Overall, you can't beat the price for what you get. And you can use the coffeemaker top on any other travel mug. Melitta just needs to figure out how to make the lid a little tighter.

"simplified coffee making"
Having tried to balance a Melitta coffee filter holder on other mugs with various sucess, it is very nice to have a mug that specifically is made to hold the filter. In addition to a nice fit, it is possible to look through the bottom edge of the filter to observe the amount of liquid in the cup, making for no more surprises when it overflows. The mug itself is lined with stainless steel and has no inside gaskets or other parts that can absorb coffee and tea tastes and stains, so clean up is a snap. While not keeping the coffee hot for hours and hours, it does nicely for about 45 minutes or so.

"You are only getting a brewing cone."
I purchased the Travel Mug Coffee Maker for my
87 year old mother. She enjoys a good fresh cup
of coffee in the morning and does not like the hassle
of using the coffee pot for a single cup. She has used
the brewing cone several times and enjoyed it immensely.
The mug, however, is totally useless. The first mug we
received had to be returned. The lid only rested on the top
of the mug. It did not attach in any way. We returned it
for a replacement which is only a slight improvement. This
one gives a good impression of a lid that will stay put but
is totally untrustworthy. My mother can not count on it to protect
her from a cup of hot coffee spilling on her lap. She
brews the coffee in a regular mug and will probably use the
Melitta Mug to root cuttings. This said, I would purchase
this item again, recognizing that the brew cone is all that I am
getting to make it worth the price.