... because it's based upon a limited number of shared experiences and also limited to my, initially, very challenging experience of buying GIF Animator 5.0 via the TBYB route.
The warning...It appears that if you download the Try Before You Buy (TBYB) version and subsequently decide to buy the program, it may be better not to Buy from the Splash screen; but rather, it may be better to delete the TBYB version completely* and then buy the program by the direct purchase route. [*Settings > Control Panel > Add or Remove Programs... ; and a Search for "Ulead" to pick up any stray bits.]
In my experience (and of some others)...1) The TBYB version is not completely eliminated during the "upgrade" and this can cause Ulead plug-ins not to recognise the existence of the host program (GA5, in my case) and, thus, fail to install.
2) No order number appears to be provided when you "upgrade" from TBYB which means that it can be very challenging to discuss problems with Support (i.e. they want the order number before processing the concern).