Tera Echo has been around over 7 years when writing this, and it still seem sto be more of a secret weapon pedal than an all-rounder found on many pedal boards. This is understandable, since i my experience the effect is pretty unique sounding and needs a little thought and experimentation before fitting the bill.
The control are intuitive for anyone who has ever used any digital delay pedal - on paper. In practice, how they react to the sound and how you play is the part where experimentation comes to play. Freeze function is a neat add-on and in times very useful and expressive, especially when playing by yourself some ambient part that need to sound BIG. There's no tap tempo option, but personally I don't see it necessary or as a flaw with this type of delay. Work quality, design and durability is your typical Boss standard: perhaps not very inspirational but sturdy and functional, a pedal to last for life and to next generation.
In my ears Tera Echo sounds beautiful, both controllable and chaotic at same time. All set to 12 o' clock it is an instant Esoteric (a legendary UK Doom band, for the uninitiated ;) ) sound machine, and you can get any type of ambient soundscape out of it, from clean to high gain, pretty subtle to very extreme. It reacts to the dynamics of your playing, which is just great, although it needs some practice in understanding _how _ it reacts to your picking and strumming. There is lots of potential in small package and hours of fun and unique spices to have in your sound and songwriting / arrangement.
It does not do simple and clear digital delay, keep that in mind when pondering whether to have this pedal or not. It can also get into pretty wild oscillation in quite an early setting of the Feedback control - I'd like to have a footswitch or expression pedal option for controlling the feedback remotely.
Tera Echo has now been an on/off pedal board option for about 5 years. In my active bands its usefulness have been limited and in one time even deteriorating, but it's not the pedal's fault. All in all it's a wonderful device in creating ambience to your guitar tracks, and I'd like to try out with a synth some day, too. It has been a keeper and I will hold on to it in the future.