Ahh, ok. The fee, I would say, is irrelevant. You would save far, far more than £3.99 per month. In fact, many hundreds (if not thousands) of YNAB users have found that to be true.
But, if you can't get to grips with it, fair enough. It's a real shame, though, because it's a cracking system, and I believe it's life-changing. I've been using it for a number of years, but this year, I decided to get to grips with my utilities and other outgoings, to really save money.
Because I have a line in YNAB for every regular outgoing, it was really easy to look at each one and run a check for any savings that could be made. I've saved £50 pm in real terms on my gas and electricity (£4 in actual terms - my old supplier wanted to increase my tariff by £46 pm as I came out of a fix), £40 pm on phone/broadband/TV, £70 pm on mobile phones, £10 pm on Netflix (cancelled), £187 refunded due to being excessive insurance cover from Domestic and General, £120 refund due from Scottish power for overpayment, £9 reduction in union fees as I realised that it wasn't all compulsory, so asked them to take the voluntary aspects off (I have to be in a union because I'm a nurse). So £175 per month saved in the last two weeks, plus £300 due to be refunded, which was painless because I had all the information available through YNAB.
As for other products, I think Ontrees is very similar, but I would agree to be cautious about the 3rd party authorisation issues. I couldn't use it anyway because I'm with Co-op bank and their log in method foxes 3rd party log in portals.
Generally, all money management systems will require you to categories the transactions, and they are all essentially spreadsheets that look pretty.