I'd go with the Instek. I've seen some of your other posts and threads elsewhere Zerotolerance and I think the DDS generator would be fine for your needs and I know you'd be fine with the $150 expense. Then you'd have a good basic test bench setup: scope, function generator, power supply, and some good DMMs.
Just realize that DDS generators don't have great distortion specs, so you won't be able to get high quality audio signals for testing. But that can be fixed by using a CD with pure waveforms if that kind of thing is important to you. I've got a couple of DDS generators that are loaners; I use them quite a bit and am happy with them.
A couple of comments. First, make sure you have some good probes to use with your scope. Also make sure you know how to use them properly and compensate them correctly. Second, you're going to want to have some methods of making interconnections between the things you test and your test equipment. I long ago standardized on using RG-58 cable with BNC connectors, mainly because most test gear uses BNC connectors. I also use 4 mm banana cables and BNC to banana adapters. Two suppliers' equipment I've used are Pomona Electronics and Cal Test Electronics. You may be a bit taken aback by the cost of some of the items, but with care, they'll last a long time. I'm still using some Pomona banana patch cords I got over 40 years ago and some HP coax cables I got 30 years ago.
I haven't looked up the specs for the Instek, but the typical DDS generators I've used (a few different models of HP and B&K) typically have their sine waves go up to the rated frequency of the generator. More modern ones also have the same spec for their square waves or sometimes about half the sine wave frequency. Then the other waveforms like pulse, triangle, sawtooth, etc. are typically at substantially lower frequencies. For example, an older B&K model would put out sine waves at 80 MHz, square waves at half that, and triangle waves at 100 kHz. Newer equipment does better.