I'd say the quality coming in is of a high standard but I believe 3 games in is too early to judge whether they are "upgrades"....nethertheless this is my thoughts so far;
Fabianski for Vorm - So far has been a lot more solid/dependable/domineering than Vorm. His shot stopping hasn't been tested properly yet (Made a very good save against West Brom though)
Fernandez for Chico - Impossible to make a judgement as I haven't seen him play. On the face of it his pedigree points to an upgrade....he'd have to be going some to improve on Chico though, we'll see. He represents an extra £6m invested in this position.
Siggy for Michu - A superb player and fits our team perfectly. He was totally wasted out on the Spurs' left wing and I hope we don't ever make that mistake with him. He's a natural no.10 and links up the midfield, wingers and Bony perfectly....Whether he's an upgrade on Michu is a very difficult question. Michu was a World Class finisher and worked his bollocks off for us, some of his passing was top drawer too....I feel a lot of Jacks diminish Michu's achievements far too easily, going on about last season (he was injured FFS!). Let's not forget that the whole world was talking about how good Michu was, not just us...he forced his way into a world class Spanish squad FFS!
So I won't say Siggy's an upgrade, but he's not a downgrade either...they are just different types of players. I'd say Siggy is a suitable replacement and has made a great start to the season.
Re: the money
It wouldn't matter if Siggy was playing like Messi in his pomp, we still got done on that deal. £8m bid was accepted from Palace so that is what he should have cost. LB's being chased by clubs with CL aspirations were changing hands for a lot of money. If we sold Ben for £12-15m and got Siggy for £8m it would have been fairer. If we'd conducted the Vorm business fairly and our cut of his transfer fee was £1.5-2m, I make us £5.5m-£9m down on the deal. Nevertheless I'm satisfied we got Siggy.
Tom Carroll (Loan) for Canas - They are totally different types of player. I enjoyed Carroll's cameo against West Brom and my hunch is he'll prove useful. Regardless, Canas was a DM and in my opinion the DM position is a position that we are weak in. So I'm going to have to say, promising as he is, he represents a downgrade to the balance of the squad.
If we paid up Canas' 2 years wages, that will have cost us £1.1m....I have no idea what Carroll's loan fee and wages are but after a year's development in the Prem we won't benefit from any added value he might accrue.
Jefferson Montero for Pablo Hernandez - Hernandez, when he was fit and had played himself in, was mercurial. Our most creative player....but he was plagued by injuries and when he was coming back from injury he could be very frustrating indeed, 90% pass completion to the opposition on times

Montero, I was in favour of signing at the start of the summer. Didn't know if he would adapt, there was a risk there...he is electric. Very exciting player and to me, even though it's far too early to reach conclusions (he could get an injury next week and repeat the whole Pablo saga) I reckon he is a significant upgrade. Not in terms of quality, I suspect that Pablo at his best does as much damage as Montero at his best, but in terms of the likelihood of being a threat consistently over the whole season(s).
Money was rumoured to equal out but since then all we've had in terms of info is that Pablo left for a "small fee".
Bafetimbi Gomis for Leroy Lita/Vazquez (Vazquez wasn't our player so Lita is more accurate IMO) - Massive upgrade here, no doubt. Don't come cheap though.
His agent was putting about that he required £100k a week (no clue whether that included any signing on fee or not) and was touting him around the Premier League. Widely reported that West Ham and Newcastle were interested and that Newcastle offered him £75k a week. Impossible to know but I'm going to speculate that we will have had to agree at least a deal of 80k a week....if we go on the conservative side and say that this includes the signing on fee we can conclude that he will be paid at the top of our pay scale (I'll guess 50k a week, as I read a report claiming that was Bony's wages once) and the signing on fee is the balance....30k a week over 4 years = approx. £6m
His contract runs out when he is 33. Expensive, and risky, but (in my campest voice) I like him.
Marvin Emnes for Pozuelo - Emnes has proved a useful substitute in a variety of positions and he could be successful here but to me this deal represents a downgrade. Pozuelo had a lot of natural ability, a lot (that's why larger clubs than us had been watching him)...a little wild, undisciplined, sometimes took the wrong option....but he was young and could be coached. He had lots of potential ability wise and transfer value wise.
Money: Emnes cost £1.4m ish? Pozuelo was signed on a free and was let go, as far as we know, for virtually nothing. Bad business IMO
Youngsters
Barrow's the one that excites me (cost £1m or so). Who knows on
Kingsley but I'm impressed at what he achieved in Scotland given that he's so young.
Overall
We've replaced what we've lost with good quality but it has cost us. I can't say we are stronger as a squad as we haven't fixed the long standing squad issues, namely;
GK - Quality young back up keeper (Maybe we will recruit one when Tremmel leaves next summer....or maybe Tremmel will stay?)
RB - Young long term replacement for Rangel. Tiendalli has started off well this year, but he has had good spells before....last season he played more games than he has played yet and IMO proved to not be up to it. Not slagging the guy off, he's capable of good performances at this level. He's just not the answer.
DM - Long term replacement/competition for/partner of Leon
We've also got a new issue;
LB - Last year Taylor was Ben's back up. This year Jazz is Taylor's.....this, on the face of it represents a downgrade....I hope Jazz steps up and proves me wrong, I really do
1 more minor issue that we had last year and this;
WG - We have 3 senior wingers when ideally we would have 4 (I realise the feasability of this might depend on budgets). The situation is slightly better than last year though as we have young
Barrow who is a left footer who can play on either wing as well as up front...last season we had Lamah (who wasn't as bad as some make out!) but Barrow is ours so that's better....also we have an improved, older, Alex Bray. Last season we had Gwion Edwards who we made £700k on.