The Tessy is a more basic version of the Tippa, and in turn there were a number of different Tippa models/generations. Similarly, Erika made a large number of different portable models. I would not pay a lot of money for any of them even though I'm a big fan of the Adler Tippa, TA Tippa 1, and some of the Erika portables. Could you be a little more specific as to which models you're looking at?

The Tippa is very common overhere (I live in The Netherlands), so I guess they must have been a sales success. I think the machine is clever designed and easy to service. The key action and touch is one of the finest I have experienced so far. Other perks are good ergonomics, which make it an excellent lap-typer, and a low sound profile.

However, Tippa's are extremely delicate typewrites. I have bought six of them, all were used nor serviced for decades. All had problems. I have spent a lot of time working on those typewriters. I have replaced a spring motor, swapped carriages, adjusted carriages, replaced an universal bar, replaced a type arm, replaced type arm linkages, replaces backspace linkages, and worked a lot on the escapements, bells, margins stops  and the spacebar.

The reason for this is that I think the Tippa-design leaves little room for error. All parts seems to be designed to operate in extreme small margins. And because the Tippa is an ultra-portable, parts are pretty thin and light. This makes the parts prone for damage and therefore the machine prone to malfunction

As with a lot of typewriters, over the years little design improvements were implemented, but the quality of the used materials decreased. My older Tippa's (from 1964 and 1965) have a very sensetive escapement that causes a lot of problems. Mainly overprinting characters, an inconsistent left hand margin and an unreliable working backspace key.

These problems were fixed in my later Tippa's (from 1971) with a slightly redesigned escapement. However, due to (I suppose) worse quality metal the key levers do not work always as designed, resulting in unpleasant typing because some keys hit the spacebar support rod.

Based on my experience with old Tippa's bought from old people, I consider the Tippa as a high risk, high reward typewriter. There is a pretty good chance your Tippa has problems. But, if it doesn't have problems or you can fix them, you have a very user friendly, nice typing machine.

Because of the risk involved, I would never buy a Tippa online if it cost more the 30 Euro's, unless it is serviced by a professional.

Please let me know when you need more info about the subject. If you wish I can make a list of all the possible points of failure you have to check for.

If you decide to buy one, choose an older model. The escapement problems can be fixed, problems because of bad material not.

Kind regards,
Lau